codes: p1298- manfacurer control. fuel air metering
p0141: o2 sensor heater circuit malfunction. bank 1 sensor 2
p0135: o2 sensor heater circuit malfunction. bank 1 sensor 1

idles bounces between 1500rpm and 2800rpm. searched for a vacuum leak and couldnt find anything. even put a fog machine and still nothing.

now i searched and got similar results. first code didnt exactly show up but the description was the same. and others also had the two other codes come with the first code. majority of the time ppl said to clean the iac. and i did but still didnt help. (maybe the thing too a crap and i need a new one?)
anyone got any other ideas? this happened a few days ago when the weather went from 20deg to 40deg. before all this it drove fine and with out a problem. then after work i get this idle problem out of no where.

 

I had a problem with IACV and swapped one from another throttle body and cleaned but still had the problem. Thought for sure I had a vacuum leak but couldn't find one. Got a new one and the problem went away

 

u got a new iac?

 

i had that problem after doing my valve adj. and it was the iac gunked up. Cleaned it really well with carb cleaner.
Try plugging the IACV with your finger, if the revs stabilize then it's the valve.

 

i cleaned it really good. ill try plugging it later today. but when the car was running with the idle problem i unplugged the iac and the idle was bouncing around 1500-1700rpm not 1500-2800. so would that mean its working? or it doesnt matter

 

Yes and I agree with gnuts if you plug it it will stabilize.

 

havent had time to try it out but i did get a spare iac from a friend. ill clean this one out and try it.

 

swapped in the other iac and didnt help. when i plug up the iac hole the rpm drops down to where the engine is about to stall.

 

so sounds likely to be a vac leak. Spray carb cleaner around gaskets (intake manifold, throttle body etc.) while the engine is running. where the rev's stabilize is your leak.

Did you do any engine work recently?

 

check the egr in the upper mani too, that has been known to cause issues too.

 

unless the runner got cracked somehow (happened before and i rewelded it) i couldnt find a leak in any of the hoses and the egr was clean.

 

try spraying carb cleaner to see if you have a vacuum leak. Also I swapped a couple of different iacv figuring more than one couldn't be bad but I was wrong. Try the carb cleaner first.

 

Don't clean the iac before trying it. I have tried the whole cleaning iacv before and it led to problems half the time..so. Don't do it unless u have to. Are you sure you did not mess up and connect sensors in the wrong spot... Cause it can happen there around the throttle body areaish... I Dont kno when this problem occurred but if you had to put a bunch of connectors back on I think it may be s simple as that. Try it out...

My guess is its something uve overlooked and I doubt u thought you may have swapped connectors

 

didnt mess up the connections. drove fine to work then it sat for 10hrs and when i started it back up, thats when the idle problem happened. no one touched the car for those 10hrs. and no recent engine work was done

 

muthafudgin car gremlins man, they find cars to infiltrate when they get cold or its raining outside.

 

It ran great when it was cold. As soon as it hit high 40s the problem occured.

 

so my guess is ur looking at a bad temp reading?? therefore u need to replace the intake temp sensor (s). I would do an ohm check on everything related to idle and intake.. that should let u know if a sensor is causing the problem or if u gotta look elsewhere


i feel for you pal.. and i wish u all the best.

 

dont think its the temp sensor. started the car today ( 36deg outside) and it was idleing at 1400rpm then once it was warmed up it started bouncing around again. sprayed carb cleaner around the tb, vacuum hoses, im runners, im gaskets and no change. another code did pop up.
p0505- idle control system malfunction. everything is hooked up.

 

I still think its the IACV i had the same exact problem and couldn't get it to go away after trying for a few weeks I got a new IACV and the problem went away. I would also check and make sure you don't have a crack in your runners

 

im getting a new iac. i sprayed carb cleaner like u said where i can. also when i had the im off i checked the runners. and didnt see any cracks.

 

I just cleaned mine not to long ago now its working just fine. Make sure you do a really good job at cleaning it and make sure the magnet knob turns freely. Also clean the surface where it makes contact with the gasket.
Here's a little fake video after I cleaned mine.
It looks like I was having to much fun with it lol.

 

I'm gonna clean it out one more time. This time taking the sensor off

 

That's how its suppose to be cleaned, with the sensor removed. At least from what I was told.

 

so it was still stuck. cleaned it out again and it spun freely. turned on the car and it idled great. until i gave it so gas. then it started bouncing between 1000rpm and 1800rpm. much lower then before.

 

Did you try a new one? other than the IACV the only thing I can think it would be is a vacuum leak but you already tried spraying carb cleaner to see if that worked.

 

have not tried a new one. going to take the intake manifold and runners off tomorrow to see if they are not cracked.

 

wait a second, if my car idles fine before i hit the throttle, then it cant be a vacuum leak. bc if it was then the idle would bound around for the moment i turn my car on. right?
ordering a new iac.

 

Kind of a shot here but another reason you could have idle problems would be air in the coolant system.

 

ive read about that years ago but i dont have a coolant leak and i didnt do anything to the cooling system since i put in my clutch and that was two months ago.

 

put in the new iac and cars runs good. a bit rich but idles and drives good. but i still have the first 3 codes that i had before (i cleared the codes and unplugged the battery prior to replacing the iac).
now, i did take off the sensor that the motor mounts are hooded up to and then the other vacuum line goes to the IM. not sure what thats called but would it throw the codes: p1298, p0141 , p0135? i did cap off the port on the IM.

 

Glad you got the idle fixed. It drove me crazy when mine did that. I wish I could help you with the other problems.

 

yea, thanks for everyones help. ill see if driving the car tomorrow will clear the codes. if not ill plug that sensor thing back in

 

so this is the parts that i removed.
50913-S87-A81 VALVE ASSY., ELECTRONIC CONTROL MOUNTING SOLENOID

 

check engine light went away and car drives great