Intermitted Power Loss, Please Help!

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Mazda, Protege5
I have been having an intermitted issue(s) on my 2003 Mazda Protege5 with 150,000 miles and a JDM motor. I cannot find a solution, can someone please help?

The problem started last winter, and was not nearly as bad as it is now. The symptoms went away in the spring (warmer weather?), but came back bad starting in October when the cold weather came.

The symptoms about after 15 minutes of driving, the motor starts to lose power. It starts as a split-second loss of power that jerks the car. After a while, it leads to more violent jerking under load, and sometimes total loss of power. I would be driving down the interstate, and the RPMs would start to drop as I press harder and harder on the gas pedal.
I was getting stalls a lot too until I replaced my fuel pump/filter, but sadly, this did not fix the power loss issue. Before the fuel pump replacement, the P5 lost power totally one day and would not restart for a few minutes.

I very rarely get codes, but the ones I have gotten are
-P0090 - I stopped getting it after replacing the FPR
-P0340 This happened twice, and only during the most violent jerking/power loss

Things I have done to try to fix the power loss issue
- Replace the air filter
- Replaced a somewhat new coil pack that looked damaged
- Replaced the FPR
- Replaced the Fuel Pump and Filter - a huge pain in the butt due to rusted screws. The car seems to drive better, no stalls, but the power loss has not gone away
- Swapped the Camshaft Position Sensor with a friends from a MSP

Thoughts on what else it could be:
-Engine coolant temperature sensor this would explain why it might ride like crap after the vehicle warms up. I had this issue on my MR2 Turbo, but I had a CEL with this, which the P5 does not have any.
-Plugs - these were replaced in the last 5k miles, but I might just replace them as plugs are cheap.
-Timing issue I have no idea if the belt was ever replaced, but if it was the belt, why would the symptoms be intermitted? Maybe some other timing related issue?
-wiring/electrical issue this is what I am mostly worried about, since it is a intermitted issue, I doubt it will be easy to find a solution to the problem if there is a short or damage wire somewhere.

I have done quite a bit of research on the issue, but I cant figure it out. I have been using my truck to commute with, but I really need my car back. I also dont want to keep on throwing parts at the car. It is becoming too expensive. I do have a MSP to borrow parts from.

Anyone have any thoughts of what to do next?
 
If I had to guess, not knowing anything about the engine, my first guess is something is wrong with the cam timing --- perhaps the cams are out of sync. The belt/chain or tensioner might need replacement, or one of the cam bolts might be loose.
 
If I had to guess, not knowing anything about the engine, my first guess is something is wrong with the cam timing --- perhaps the cams are out of sync. The belt/chain or tensioner might need replacement, or one of the cam bolts might be loose.
Thanks for the reply. I thought about something timing related, but if the cams were out of sync, would the issue be intermitted like it is? or would it be an issue that is always present?

I am not sure, but I would bet that the timing belt or tensioner was never replaced. I really don't want to do it, as I planned to only use the car for the next 1-1.5 years, and I didn't want to invest too much more into the car.

Maybe I will remove the valve cover and take a look. But again, if the cam was off due to jumping a tooth, wouldn't I experience the issue all the time? and not just when the P5 drives for 10 miles first?
 
I think you should swap coils from the donor car.
Coils like to fail in strange ways and they're quick and easy to swap.

Here's the big list for reference.



Check the connection and wiring to your cam sensor. You did throw that code and a bad cam sensor is at the top of the list.
 
I think you should swap coils from the donor car.
Coils like to fail in strange ways and they're quick and easy to swap.

Here's the big list for reference.

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Check the connection and wiring to your cam sensor. You did throw that code and a bad cam sensor is at the top of the list.

I was just going to also suggest ignition coils. Sounds like a misfire to me and the coils are not uncommon to fail, especially given your age and mileage. these will definitely be an intermittent failure and not always throw a code unless the misfire caused by the failing coil is bad enough. worth checking your plugs also to see what they look like, is it running lean/rich when it fails? are the plugs wet or fouled? bad coolant temp sensor or even an oxygen sensor can sometimes cause problems like you describe once the car warms up and they start functioning (the car ignores these sensors until it reaches proper operating temperature).

potentially a wiring issue but i would start with coil before digging too deep.
 
I think you should swap coils from the donor car.
Coils like to fail in strange ways and they're quick and easy to swap.

Here's the big list for reference.




Check the connection and wiring to your cam sensor. You did throw that code and a bad cam sensor is at the top of the list.

Thanks for the reply,
I already switch out one coil that was under warranty and was damaged. I will swap the other one soon.

As for the Cam Shaft Position Senor, I swapped it with one from a MSP and no improvement. I cleaned the connector, which looked fine. From my research, the P0340 CEL code is a "catch all" type of code, and could trigger for many, many different reasons. Considering that I have only seen the code twice, but the issue is present all the time, I am thinking that it is probably something that falls into the "catch all" category.

One of the biggest issue I have with trying to find a solution to this problem, is that it does not appear until I am driving for a while. I can do 2/3s of my commute to work before I start having issues. Any changes, parts swapped or replaced, checking and cleaning of connects I do, I will not see if I was successful until I am driving for about 5-10 miles.

With the crazy cold weather we have been having, I have temporarily given up on messing with the car, but when it warms up again, I plan on trying a few more things....
 
Sounds like a misfire due to faulty ignition coils. Be sure to also replace all spark plugs.
 
I was just going to also suggest ignition coils. Sounds like a misfire to me and the coils are not uncommon to fail, especially given your age and mileage. these will definitely be an intermittent failure and not always throw a code unless the misfire caused by the failing coil is bad enough. worth checking your plugs also to see what they look like, is it running lean/rich when it fails? are the plugs wet or fouled? bad coolant temp sensor or even an oxygen sensor can sometimes cause problems like you describe once the car warms up and they start functioning (the car ignores these sensors until it reaches proper operating temperature).

potentially a wiring issue but i would start with coil before digging too deep.

I appreciate your thoughts.

I replaced both coils 14 months ago along with the plugs and wires, and replaced one coil again 2 months ago when I saw that it was damaged.

I don't think it is the coils though, due to the lack of codes for it. I bought the P5 new, and had a coil go bad a few times, there was always a code when it repeatedly missed, and the CEL would flash when it was really bad. That doesn't happen here, basically no CEL 95% of the time when the problem is happening.

I will swap the coils with my friends MSP, and I am going to replace the plugs again, but I don't have confidence that will solve the issue.
 
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Sounds like a misfire due to faulty ignition coils. Be sure to also replace all spark plugs.

I plan on replacing the plugs again, and I will swap out the ignition coil. I am waiting for the weather to warm up a little.

But have you (or anyone else) ever had a coil misfire repeatedly to the point that you lose power, stall, and can't restart your car, and not see a CEL from it? Just curious...


A side note, I haven't seen the stalling issue since I replaced the fuel pump, so I am wondering if there could have been a compounding of issues due to a weak fuel supply.
 
I plan on replacing the plugs again, and I will swap out the ignition coil. I am waiting for the weather to warm up a little.

But have you (or anyone else) ever had a coil misfire repeatedly to the point that you lose power, stall, and can't restart your car, and not see a CEL from it? Just curious...


A side note, I haven't seen the stalling issue since I replaced the fuel pump, so I am wondering if there could have been a compounding of issues due to a weak fuel supply.

Your car does not have only one ignition coil. there is one for each of the 4 cylinders. you have to make sure that all 4 of them are in good working order.

to answer your question, yes... My BMW had one faulty ignition coil and it would not trigger a CEL unless I was at a higher RPM which then triggered a misfire. the car would stutter while trying to gradually increase your speed on the highway just like you mentioned, so I am convinced you got a faulty coil somewhere. I was also thinking that it could possibly be an injector, but that would certainly throw some sort of misfire code. an ignition coil will not always do that.
 
But have you (or anyone else) ever had a coil misfire repeatedly to the point that you lose power, stall, and can't restart your car, and not see a CEL from it? Just curious....

Yes... Coils for our car can be a huge fricken PITA.

They can be bad brand new out of the box. If they aren't missing enough, they won't throw a code.

Whenever our car has weird symptoms that don't seem to make sense it's always good to start with coils.

They're not too much money and are easy to replace.
 
Your car does not have only one ignition coil. there is one for each of the 4 cylinders. you have to make sure that all 4 of them are in good working order..

We have two coils for our car, using the wasted spark setup.
 
Your car does not have only one ignition coil. there is one for each of the 4 cylinders. you have to make sure that all 4 of them are in good working order.

to answer your question, yes... My BMW had one faulty ignition coil and it would not trigger a CEL unless I was at a higher RPM which then triggered a misfire. the car would stutter while trying to gradually increase your speed on the highway just like you mentioned, so I am convinced you got a faulty coil somewhere. I was also thinking that it could possibly be an injector, but that would certainly throw some sort of misfire code. an ignition coil will not always do that.

Thanks for the reply,

There is a little bit of misinformation in your post. The P5 2.0 has two coils packs, each is over the #2 and #4 cylinder. The are plug wires coming off of the coil for cylinder #1 an #4.

Maybe I wasn't clear in my post. I replace both of them in Nov 2016, along with the plugs and the wires. I replaced one of the two new ones 2 months ago when I started having issues. The coil was damaged, so I swapped it under warranty.

About having the misfire without a CEL, I believe it happens as it has happened to me, but with how badly the vehicle was missing, I find it hard to believe that I haven't gotten one code from it.

I plan on swapping out the coil packs, so I guess I will know if that is the issue soon. Man, I really hope that is the issue....
 
Yes... Coils for our car can be a huge fricken PITA.

They can be bad brand new out of the box. If they aren't missing enough, they won't throw a code.

Whenever our car has weird symptoms that don't seem to make sense it's always good to start with coils.

They're not too much money and are easy to replace.

I think I have replaced my coils in my P5 3 different times total, I never had a new one be bad, but I have seen other people get bad ones in the reviews.

The two I purchased 14 months ago have a limited lifetime warranty, so if one of them, or both ends up being bad, it won't cost me anything to replace them.

I just wished it was an issue that I could swap them and check to see if it works. It just sucks test driving the P5 for 10 miles and not sure if I am going to break down or not.
 
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I keep my old coils in the car (they were still working) just in case my car goes crazy and stops making sense.
I can swap them on the side of the road.
 
How do your wires look? Possible old plug wire grounding out or causing a weak spark? Plugs and coil packs are newer but how about the wires?
I just had an issue car would just turn off while driving it. No symptoms of it happening just bam! Its off. Turns out the crank sensor had chaffed just below the plug against the lifting eyelet causing it to ground out and kill the engine. Took 3 days to find that. Might be a wire worn down near the cam or crank sensors
 
Inspecting your crank sensor is part of the procedure for inspecting your cam sensor.
The car will run with bad cam sensor info but the ECU will kill the engine with bad crank sensor info.

It's easy enough to quickly check the crank gap and check the teeth.
The electrode/pick up on the crank sensor likes to corrode and increase the gap.
Maybe swap it out from the MSP cause it's easy enough to do.



The part that bugs me is that his car will probably start running fine in a few months when spring comes ??

That to me suggests our fussy coils or maybe the ECT as he suggested... or maybe the IAT sensor ??
 
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Thoughts on what else it could be:
-Engine coolant temperature sensor – this would explain why it might ride like crap after the vehicle warms up. I had this issue on my MR2 Turbo, but I had a CEL with this, which the P5 does not have any.

There is two codes for the coolant temperature sensor... Basically just for a broken wire or a shorted wire, not for bad data or "performance"...
That might be something to check or swap if coils don't fix your problem...

The IAT has a "performance" code.

 
How do your wires look? Possible old plug wire grounding out or causing a weak spark? Plugs and coil packs are newer but how about the wires?
I just had an issue car would just turn off while driving it. No symptoms of it happening just bam! Its off. Turns out the crank sensor had chaffed just below the plug against the lifting eyelet causing it to ground out and kill the engine. Took 3 days to find that. Might be a wire worn down near the cam or crank sensors

The wires I relatively new. They will purchased in Nov of 2016. I have a few sets of old ones that were not necessarily bad when I replaced them, I will swap out the wires and check it out.
 

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