Hello all,

I have been doing alot of reading and trying to track down my problems. First i have a 1998 Audi A4 2.8 30V with about 68k, timing belt/water pump has not been done yet. I am going to bring it to Audi to get the Recalls(which i am sure some haven't been done yet) done.

Now my problems are with rough idling at times and idle dropping sometimes when i come to a stop especially harder than normal stop. The car doesn't stall but it seems like it wants to.

Also for the last 2 weeks when i fill up on gas the car has a harder time starting and have to hold gas down to crank it over and hold for 20-30 seconds.

I used a Generic ODB2 checker and got P1136 and P1138. Yesterday i finally got my Vag-com installed and working and received codes P1136 , P1138 and P0455 (Evap Leak). Now i did some searching already for some Vac Hoses but can't seem to find any cracked. I ran the Vag-Com at idle and the MAF G/S is about 2.7 i believe and went up to 1300 or more at redline in first gear. Is it correct for me to assume that my MAF is not going bad and its actually a VAC leak casusing my problems?

Thanks for you help ahead of time.

 

The "hard to start" issue kinda points to a bad Coolant Temperature Sensor. Its plugged into a small coolant pipe on the rear of the engine. A green or blue plug usually (also sometimes black)

Id try that first as the plug only costs $2-$3.

 

P0455 is caused by a large air leak and that throws the other 2 codes, check exhaust/intake/air system for leaks

 

Brrman: Thanks for the info, you think this will cause the car to not want to start after refueling the car?

avant80@2.6: Thanks also i assumed it was a Vac Leak somewhere, i was just hoping i could narrow it down. I was reading about the Propane test...which i am not comfortable with. I was hoping to find a Smoke Machine to test for leaks. Any thoughts on where i should narrow this search down?

I am probably going to order about 3 feet of Vac tubing from ECS and the Coolant Temp sensor.

 

intake seems to be a common area for pipes to come off ( under the intake/inlet manifold) other areas is the MAF pipe to the intake/throttle body it splits with heat and age also the pipe clamps come lose

 

Hmm - so its only hard to start after filling the car? Sorry I missed that tidbit.
I would forget the coolant temp sensor then.

Do you top off the tank when you get fuel? Don't do this. There is a vapor canister as part of the evap system which provides air pressure in the fuel tank. If you overfill, you are likely letting fuel into this canister, thus reducing the air pressure barrier - hence the hard to start... Same type of scenario when you have a leaky fuel cap and get a evap system leak CEL, though on a much smaller scale.

 

Ah thanks for the clarification. I did fill up the tank for about 5 times consecutively and only had the problem on the last 2 times. This morning though i put in only $20 which put the tank at 3/4 and i still had a problem starting. Makes no sense..i figured there was some sort of air being caught in the tank and not releasing...but that shouldn't happen. Now don't forget i am getting the 0455 code which is EVAP Leak with the other 2 O2 sensor codes.

 

Thanks thats what i also gathered from my reading around. I will look at it this weekend. I appreciate the help and any more info would be welcomed.

 

i'm dealing with the same exact problem.does'nt matter how much is put in.it's not the fuel cap,it's not the purge valve(atop the air filter housing)keep us posted please as i will also.had same prob. with the almost shutting down,changed the fuel filter and all was well.we might have a bad evap can from what i've read, i gotta check at leak detector,evap can.,and fuel tank hoses,i'm tired of this problem also.does your car feel kind of doggy.

 

the fuel filter replace was for almost shutting down on braking.i don't think there are any recalls that are needed fixing unless you live somewhere really cold.i'm in socal.as i tell everybody i can .if anybody is going to do waterpump,timing belt, or anything in service engine position,be sure to replace the front engine mount,it's a factory ten dollar part,but dealer charge 260.00 if done alone or seperate.i did mine myself because the idiot that did my upper pan gasket wrong twice(reputable mechanic)didnt tell me i needed it while it was apart.twice.