i have a 99 1.8t and for the pastmonth or soi've been getting a cel with the code P1136 (left bank running lean). the cat,o2 sensors, andmafwere replaced, the fuel pressure and hoses were all good, but it keeps coming back.my mechanic had his friend who was an audi tech look at it, and he brought it to the audi dealership in town and they couldnt find anything wrong with the car except for a small crack in a breather hose under the intake manifold, so they replaced it and the cel came back.This was about a week ago. then yeaterday i was letting the car warm upand the cel started flashing.does anyone have anyclue what it could be cuz im out of ideas

 

Well now that your engine light is flashing its miss-firing so that tells you the ICM (power output stage) is bad so your gonna need a new one of those. (sits on top of the air box)
Its possible that the O2 sensors were reading crappy readings because your ICM hasn't been working up to par, meaning you weren't getting complete combustion in the cylinder, but that would usually throw a rich fault code.
If its running lean its most possibly a very small vaccum leak somewhere which could be very hard to find, did the dealer use a smoke tester on the intake and pressurize it? Or did they just do a visual?

 

im not sure what they did, but its been in the shop 4 or 5 times now cuz of this code, so i would imagine they would have made sure it wasnt a vacuum leak. also, i started the car today and the light was blinking right away, then after a minute or two of idling it stopped and the whole way to my mechanic (about 5 miles)it didnt blink.

 

Don't drive it with it flashing, your damaging your engine and your cat converter. Buy that ICM from www.ecstuning.com and see what it does.

 

https://www.audiforums.com/m_361655/tm.htm

This does not explain the misfires. Read and post the codes.

 

yeah i read that thread while searching and i checked that hose and it appeared ok. its already at the mechanic since he stopped charging me for these repairs, but when i call them monday ill tell them to try replacing the icmand see what happens and also get the codes from them. thank you very much for the input, ill repost when i have more info

 

i just talked to the mechanic and he said the only thing he can thinkof is taking out the k&n and putting the airbox back in to see if that might work, so ill try that today and post whether or not the light stays off...wish me luck!

p.s. how much of a reach is he making or is thisa legit theory?

 

A restricted air filter would still be measured accurately by the MAF - he's just scratching his head.

Were you getting the blinking CEL (misfiring notification) since the beginning? Because misfiring will generate a lean code, in addition to the misfiring cylinder(s). Was it your same mechanic that replaced all your parts listed? Usually, misfire diagnostics will take supremacy in the recognition of codes. I suspect that your parts were possibly replaced prematurely. Just my hunch: your leak was there from the beginning and wasn't sought out. Jump forward to the present and I'd wonder if the dealership ended their leak search when they found the ONE. Could there still be a small leak. And, if there was the only one leak, were the fuel trims reset?

I would second the smoke test for a leak. And examine the simple things starting with the plugs and a weak coil. The ICM is a simple switch and is either a go or no-go solid state electronic transistor pack. So, you should be getting a consistent NO FIRE if it's bad.

 

the misfire happened when i started this post, so about a week and a half ago. i got the car back today for the first time since that happened. the same mechanic did all the repairs until he brought it to audi and they found the breather hose. im not sure what kind of vacuum leak test they did but im gonna clear the codes today and if it comes back ill do the smoke test. if the lines are good ill replace the coils and plugs. thanks for the input.

on a possibly unrelated note, my cars making a whirring noise over 35 mph. it sounds like its coming from the passenger side but its not any worse turning one way or the other.

 

Just trying to follow a methodical path. Your original code was for running LEAN. And your mechanic replaced those components that he felt would answer the problem. However, it wasn't until he opted to take it to Audi that a leak was uncovered. Was the leak originally responsible for the LEAN running condition and parts were just thrown at the problem? Who knows? But, what I'd want you to avoid is throwing more parts at the problem. A LEAN running engine will throw MISFIRE codes. That doesn't imply that the coils, icm, or plugs are bad. Once a MISFIRE is generated the ECU goes into open loop and won't generate a LEAN or RICH code until the misfire is taken care of. The problem lies in whether it was a LEAN condition that caused the MISFIRE.

I agree with you. Clear the codes and IF they (either MISFIRE or LEAN) come back, perform a smoke test. But hold off on the coils, icm and plugs until (IF) you get a code.

Just my 2 cents.