Hi

Can anyone help!

I'm in the UK and my wife has a 1995 A4 1.8 20v. For a while now it has been running rough on idle and is only returning about 27mpg.

I took it into a VW specialist who said he thought it was a dirty throttle body. He cleaned this out and it seemed to be a bit better but not much. I took it back and he suggested it could be the mass airflow meter but that these didn't go wrong very often. I have sourced a second hand one and after blowing it through with carb cleaner I put it on. I also put some injector cleaner through the tank and it seemed better until that tank of fuel was used up.

It's now back to having a rough idle and the mpg hasn't improved a bit. I did try changing the plugs a while back but this didn't seem to do anything either. I'm really at a loss about what to do now and the guy at the garage has said that you could end up changing loads of parts without tracing the problem, which he doesn't really want to do. All he can tell me is that the ECU is reporting a fuel/air problem but nothing specific.

Has any one got any suggestions that I can do myself. I'm ok with a tool kit, although I had trouble getting the throttle body off, so I left this for the guy at the garage to do.

Thanks in advance for your help.

 

Have you got EGR valve checked ? It also cause rough idle + mileage problem.

 

Egr can couse rough Idle or stalling at Idle or low speeds only
If he said its A/F problem Check O2 conditon my be its stuck lean and causing
it to run rich, you have to see wat the imputs are telling the computer thats cousing
it to affect A/F ratios

 

Thanks for the replies but what is an EGR and what is an A/F?

 

a/f is your air/fuel mixture...your egr is your exhaust gas recirculation valve..it's part of your emissions system

 

i would check out your O2 sensors

 

Check 0xygen sensors or vacuum leak.

Could also be bad ignition coil or ignition module. Find someone with a vag-Com to pull any codes and see what they say.