Coming off idle hesitation...

F

Fluffy Bunny

Member

:

03 Pro5

• Aug 23, 2014

• #1

Coming off idle hesitation and stumbling idle...

Car was bought new in Oct. of 2002 - now about to reach 125K - and have a problem that do not want to spend a fortune on replacing parts that are still working properly.

At idle, only when fully warmed up, does not idle smoothly and will occasionally miss. With AC on - idles like it should. When you come off idle when missing, it will hesitate about 75% of the time and feel like it is about to fall on its face, but catches up and accelerates just fine. There is no other issues when operating at any rpm other than idle. Is not throwing any codes.

Done: plugs, both coil packs (had two go out in a 12 month period two years ago - but replace them again), new EGR valve.

My suspicion is the TPS - but it is $150 to find out if that is right or not...

Any ideas?

 

Last edited: Nov 16, 2014

Z

zackmac

Member

:

2003 Mazda Protege5

• Aug 23, 2014

• #2

I was just having a similar idle issue... replaced plugs coils and wires, didnt clean egr yet...
after i replaced them i disconnected the battery to turn off the cel and now it wont hold a charge so i dont even know if it fixed it lol.

i did a lot of searching around and found that the main idle problems are what you and i have both done... plugs, coils, wires, and egr. i remember reading something about o2 sensors but that would be the first thing to throw a code.
sorry i don't have any additional input or possible solutions but seems to me you've done all the basic diagnostic procedures

 

T

thuzil

Member

:

Mazda, Protege Heavily Modified

• Aug 23, 2014

• #3

Check for vac leaks.

 

P

pcb

The Diagram Dude

:

2002 MP5

• Aug 24, 2014

• #4

Fluffy Bunny said:

At idle, only when fully warmed up, does not idle smoothly and will occasionally miss.
Any ideas?

Click to expand...

Seafoam,...

As soon as my car starts to stumble on idle, I know it's time for seafoam,...


It may not fix your car but it's only 10 bucks to find out and your car will still thank you for other reasons,... (injectors, fuel lines, EGR, IAC, ,... anywhere there's carbon, sludge or lacquer buildup,... (including those oil drain holes on your pistons,...))

Fluffy Bunny said:

My suspicion is the TPS - but it is $150 to find out if that is right or not...

Any ideas?

Click to expand...

I'm thinkin your injectors (or maybe your IAC valve) are fouled up just enough to stumble your idle,...

 

P

pcb

The Diagram Dude

:

2002 MP5

• Aug 24, 2014

• #5

zackmac said:

i disconnected the battery to turn off the cel and now it wont hold a charge so i dont even know if it fixed it lol.

Click to expand...

Don't forget that when you disconnect your battery, your ECU has to relearn your car.

My car stumbles like mad and very nearly stalls after a disconnected battery,... it takes a good hundred miles to stabilize again,...

Clearing the code with a code reader doesn't reset the ECU and prevents the "near death experience" my car has to go through,...

 

F

Fluffy Bunny

Member

:

03 Pro5

• Aug 26, 2014

• #6

So I guess the next question is, do I drop the money to have dealer/repair shop hook it up to see if what it is doing when it is missing/stumbling when coming off idle or is it something OBDII would not pick up? If ANY of the sensors (IAC, TPS, etc) were not working properly, it would be throwing codes, right?

Thanks for the info so far - always put in a can of SF every six months or so, but have not SFed the engine in about 20K...

 

P

P-Funk!

:

Lancer Ralliart Sportback

• Aug 26, 2014

• #7

Your OBDII reader should show real time data feed from the TPS (mine can)...

Let us know what the values are.

 

P

pcb

The Diagram Dude

:

2002 MP5

• Aug 27, 2014

• #8

THIS:

PLUS THIS:

Should make your Bunny happy again,...

 

H

hotcracker69

:

Mazda, Protege5 2002

• Aug 27, 2014

• #9

I once had a radiator leak, and the idle sucked. but car drove fine. replaced the radiator and issue went away. and car feel smoother and my mpg is more steady- is worth checking.

is also worth checking the intake tube, they tent to rip at the accordion section.

1.seafoam it.
2.get different brand fuel see if it makes a diff.

 

Last edited: Aug 27, 2014

F

Fluffy Bunny

Member

:

03 Pro5

• Nov 16, 2014

• #10

Seafoam did not make a difference.

Dropped it off at the dealer all day to have them say, "We cannot figure out what it is..." Because it wasn't throwing a CEL, they did not really know where to start. They recommended changing coils, plugs, wires, and the obligatory "fuel injection cleaning." Coils are $112 each...

This past Thursday it finally gave me a CEL - #3 cylinder miss-fire. Replaced the coil on two/three - car ran fine for about 15 miles, then got a miss sitting at a stop light.

While sitting at a light, I can feather the throttle some and bump the rpms up to 900/1000 from the regular 700. At 900/1000, it has never missed or stumbled when getting started rolling again...