Z28 Still Has Rough Idle Wtf????

[MechanicalMehem]

No problem, good luck with your car and your (hopefully)swift recovery!

[Latinstal69]

Well i have the same problem on my 2001 Z28 but i asked a friend(has 12 years workin for gm) that works with me at a GM Dealership why does it do that and he told me that its something they did to save gas which the pcm lets the car lean out and picks it back up. this is only done while in park or at a stop so is your car doesn't miss fire while driving then thats what its going to be

[MechanicalMehem]

True, it will lean it out to save fuel costs. However you should never feel it inside the vehicle. Oh btw, I to am GM certified, have 2 years vo-tech, 2 years asep(automotoive service eduacational program), this is the GM training program degree(associates), 8 years at a chevy dealership, 2 years in the independent auto industry-its amazing how much I learned about cars in general after going to work for the independent. I am not saying I know everything or even alot for that matter, there is always more than can be learned by one person.

[sscamaro1384]

i got the same problem, goin on about two weeks now. i noticed my throttle cable is broken on the place where it is mounted on the bracket. orderd part but still waiting. someone told me it was a vacuum leak but ive checked and cant find one. any one else got any ideas?

[LETHALxLS1]

I know one thing about it for sure. When I bought the car 7 months back it never idled rough like this. I say rough but most people wouldnt make a big deal about it. Shit like this drives me crazy because I know what it should idle like because of what it was like when I bought it. I am just a bit picky when it comes to my car. I want my shit perfect. I guess its one of those things that will have to get worse before it can be fixed. I mean it may be the motor mounts but in my mind I dont think it is because of the way it kind of surges. I am gonna try SLICK 50 fuel injector cleaner next. It couldnt hurt anyway. Other than that I am gonna start replacing sensors like the air temp sensor and maybe clean or replace the pcv etc. until I hit on it. FK it.

[sscamaro1384]

keep me posted. id really like to know what your turns out to be.

[LETHALxLS1]

keep me posted. id really like to know what your turns out to be.

Hey is your car surging when it idles any??

[sscamaro1384]

same syptoms u described plus i am throwing the ses light with p0170 and p0174 left and right bank lean. surges at a stop light. fine while driving. came after a water pump replacement. posted it on a few forums but havent solved the problem yet

[LETHALxLS1]

same syptoms u described plus i am throwing the ses light with p0170 and p0174 left and right bank lean. surges at a stop light. fine while driving. came after a water pump replacement. posted it on a few forums but havent solved the problem yet

I see. My check engine light hasnt come on yet. I will let you know when I hopfully figure it out. I hate shit like this. I had a s-10 and it did the same shit. I replaced so many things it was rediculous and it still never idled right.

[Wheeler99WS6]

is your car an A4 or M6? Mine is a4 and idles around 500-600 when warm. if yours is a4 and idling around 900 you may have a vacumm leak. not sure what M6 idle at. kinda wondering about the fuel system also though. could be dirty injectors like you are thinking, do a search on Seafoam its an intake and injector cleaner. hooks up to the fuel rails. Maybe even a new fuel filter needed. can you have you fuel PSI checked? Just trying to help.

[LETHALxLS1]

is your car an A4 or M6? Mine is a4 and idles around 500-600 when warm. if yours is a4 and idling around 900 you may have a vacumm leak. not sure what M6 idle at. kinda wondering about the fuel system also though. could be dirty injectors like you are thinking, do a search on Seafoam its an intake and injector cleaner. hooks up to the fuel rails. Maybe even a new fuel filter needed. can you have you fuel PSI checked? Just trying to help.

Thanks for your insight on this. I did put a new fuel filter on and plugs and wires and it didnt change things a bit. I read about that injector cleaner that hooks up to the fuel rails and was actually thinking about getting it. I am mistaken my car idles at 850 which from what I read seems just right. It is a
automatic also. No I never had the fuel pressure checked. Do you think it may be the fuel pressure regulator? Do you know if a chevy dealer would be able to clean my injectors in the same sort of fashion as the way u mentioned? If they do I think I am gonna get them to do it cause of my recent back surgery. Thanks again--mike

[Wheeler99WS6]

I believe they can but would charge you an arm and a leg to do it. I believe it isnt anything too extreme to do but then again you probably dont want to do any leaning over at all. hmmm.....well if you got the cash you could have them do it or buy the stuff and pay some kid $20 to hold the bottle while you give the car some throttle while the fuel rails suck it all in. Do a search on it like I said I beleive it was easy to do, just pay a nephew or something to hold the can for ya so you dont have to lean over the engine. Dont forget to also check your PSI, could be one of those two things.

[LETHALxLS1]

I believe they can but would charge you an arm and a leg to do it. I believe it isnt anything too extreme to do but then again you probably dont want to do any leaning over at all. hmmm.....well if you got the cash you could have them do it or buy the stuff and pay some kid $20 to hold the bottle while you give the car some throttle while the fuel rails suck it all in. Do a search on it like I said I beleive it was easy to do, just pay a nephew or something to hold the can for ya so you dont have to lean over the engine. Dont forget to also check your PSI, could be one of those two things.

Thanks-I tend to agree with you. I dont think the car would act like it does from bad motor mounts. I think 1 or more injectors are a little clogged.

[edcmat-l1]

Thanks-I tend to agree with you. I dont think the car would act like it does from bad motor mounts. I think 1 or more injectors are a little clogged.

If it was clogged injectors, you would have a problem off idle also. Think about it for a minute. What would cause this symptom just at idle? How about the EGR stuck open just slightly? See it all the time on different cars. Yours may be one.
Lean left and right bank codes are almost always caused by a contaminated MAF sensor hot wire. It cooks the crap on there, insulates it and then throws the fueling off.
Just a couple tidbits from an ASE master tech/professional tuner/20 years exp as diagnostic/emissions specialist.
Pleased to meet ya'll. Hope to be a board sponsor when Brad is up and running around. Talk to ya'll soon.

[LETHALxLS1]

If it was clogged injectors, you would have a problem off idle also. Think about it for a minute. What would cause this symptom just at idle? How about the EGR stuck open just slightly? See it all the time on different cars. Yours may be one.
Lean left and right bank codes are almost always caused by a contaminated MAF sensor hot wire. It cooks the crap on there, insulates it and then throws the fueling off.
Just a couple tidbits from an ASE master tech/professional tuner/20 years exp as diagnostic/emissions specialist.
Pleased to meet ya'll. Hope to be a board sponsor when Brad is up and running around. Talk to ya'll soon.

That makes sense to me because it does run fine when I am driving it. So should I replace it or can it be cleaned? I am a carpenter but was brought up working on my own cars with my dad. I am no expert for sure. Thank you for taking your time to help me out. ----mike

[edcmat-l1]

Its pretty easy to get off. 2 bolts, 1 electrical connector. It may have just got a piece of carbon in it. Just take it off and clean it out. You can even make a temporary block off out of a can or something, just to see if it cures it. Take a can and just cut a piece to cover both ports and tighten it up under the EGR. Then just run the car.

[sscamaro1384]

i have the same problem and with the same codes. if it was a dirty maf, wouldn't the maf code be thrown by the pcm? i experiece this problem at idle only, and am very curious to find out what it is. i have cleaned my maf, but no difference.

[edcmat-l1]

i have the same problem and with the same codes. if it was a dirty maf, wouldn't the maf code be thrown by the pcm? i experiece this problem at idle only, and am very curious to find out what it is. i have cleaned my maf, but no difference.

It doesnt set ant codes. The MAF keeps right on working, its just thrown out of calibration from being insulated. So you get lean codes. Its been goin on for years. Practically since hot wire mafs have been around. Fords are notorious for it. Even on the fords, no 02 codes, only lean bank 1 and 2.
This may or may not be your issue @ idle, but if its accompanied by lean bank 1 and 2 codes, you can almost bet it is.

[sscamaro1384]

so if this is my problem, what is the solution? new maf? clean existing one?

[LETHALxLS1]

so if this is my problem, what is the solution? new maf? clean existing one?

I am not certain but I think he means get a new one or clean the connectors. Hell maybe get a used one and try it just to see what happens.??????