Stumble, misfire, no power under load issue.

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03.5 YLW MSP
Here recently my car has been feeling extra sluggish more so then normal. Well as of lately it started what felt like a misfire every now and then only under load. The car currently has no power what so ever.. literally like no power under load I cant speed up hardly to get around someone now.

I've replaced, plugs, wires, and coil pack yet the issues still occurs. The car idles fine and I can rev it no problem. However I cant accelerate worth a **** due to this misfire/stumble/no power issue. Even if I roll onto the throttle you can feel the car bog down right before its going to stumble and misfire. It does not do it to the point that it throws a CEL which is the weird part.

Now I can cruise down the road without issue its just trying to accelerate that I have an issue with. I was told to remove the vac line adn plug it off the FPR and see if that made any difference and it did not. Also the car still sounds the same while running with the MAF disconnected and still revs fine.

I'm currently trying to get a hold of one of the local MSPer's to see if I can switch MAFs for a few min just to see if that is my issue or not. I also hear that it could also be the TPS and or the IAC. However I have no ways of testing those and no CELs on the car currently.

Edit:
Another thing to note is that it really seems to be a load issue. Every time the car gets around -5 of the boost gauge it bogs and acts up.


Edit #2:

Engine Mods:
Perrin FMIC, Turbo X's BPV, Greddy SP2 catback, Perrin SRI, Stock tune and stock 6psi boost.
 
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Or a scan tool to monitor the oem o2 sensor voltages? Either the car is running very lean or very rich.
 
Also please note any mods done to car as some of us may not be familiar with your setup
 
Yes i did, sorry. When i read fpr, I was thinking an aftermarket fpr. Anyways can you get your hands on a scanner that has live data? You are using premium fuel correct?
 
These are all possible causes from the service manual:
Improper A/C system operation
Erratic signal or no signal from CMP sensor
Air leakage from intake-air system parts
VICS malfunction
Tumble swirl control system malfunction
Purge control solenoid malfunction
EGR valve malfunction
Brake dragging
Erratic signal from CKP sensor
Low engine compression
Vacuum leakage
Poor fuel quality
Spark leakage from high-tension leads
Air cleaner restriction
PCV valve malfunction
Improper valve timing due to jumping out of timing belt
Restriction in exhaust system
Intermittent open or short in fuel pump circuit
Inadequate fuel pressure
Fuel pump mechanical malfunction
Fuel leakage from fuel injector
Fuel injector clogging
Intermittent open or short of MAF sensor, TP sensor and VSS
ATX malfunction
Clutch slippage
 
problem is kicking in before boost, so thats not it. plus, fuel cut doesn't feel anything like "bogging" or "stumbling" its like a ghost stepped on your brakes for you.

Yes, but the car could be getting into boost and losing power. My car on a real hot day if I go to pass something and my RPMS are not high and the car goes into boost the wideband goes straight to 10.0 and the car falls on its face.... But he has a boost gauge he would be able to see what the car is boosting and if it was over boosting and stuff im just saying, its so easy to check why not check it....
 
Yes, but the car could be getting into boost and losing power. My car on a real hot day if I go to pass something and my RPMS are not high and the car goes into boost the wideband goes straight to 10.0 and the car falls on its face.... But he has a boost gauge he would be able to see what the car is boosting and if it was over boosting and stuff im just saying, its so easy to check why not check it....

Yeah, but if its starting to puke out before it even hits boost... it can't be a WGA problem.

Edit: Another thing to note is that it really seems to be a load issue. Every time the car gets around -5 of the boost gauge it bogs and acts up.
 
WTF? I tried starting mine without it once (not intentional), it died instantly, and threw a CEL.
Try giving it gas to get past the initial start up and it will idle and rev fine. However it wont drive. lol

You test your wastegate?
Good

Id check your WGA and fuel pressure. We have a spare bung in our J pipes you can put that wideband in....
WGA is good, no fuel in the FPR line so its good, even capped the FPR vac line and drove around no change.

correct, the NA guys have their 2nd O2 sensor there... so we get the benefit of a freebie.

Gotta find the WB first... no luck in finding it yet. lol I forgot about that bung! The sad part is I told a local MSP guy about it. (rlaugh)
 
my friend complained about this same problem on his B3 and it turned out to be IAC.
 
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