I have an issue with my Audio which I need some advice with. I have a 2003 Audi A4 Sport Quattro Avant and it vibrates and seems to missfire when at idle. If I start the engine the revs sometimes go up to 2200rpm before settling at around 800-1200rpm this also happens if I pull up at traffic lights etc bjut not all the time. There is also a vibration inside the car and it sounds like it is missfiring. Most of the time the car engine will idle at 800rpm. If I put my foot on the accelerator and rev to 1000rpm then the vibration appears to settle a bit. It is like on older cars when the tickover was not right. The car has done 70,000 miles and has recently had a new cambelt along with Thermostat, Water pump, coil packs and temp switch for the ECU. I dont want to be spending a load more money trying to find this problem with gargages so was wondering if anyone had experienced this issue and might be able to help me find out what the exact issue is so I can get it sorted.

Thanks

Martin.

 

What is a vaccume leak for 400. Check your check valves and vac lines. Thats where i would start. Also make sure none of the connections have a small tear.

 

Pa4ul,

Thanks for the info and the quick reply it is much appreciated. I will check this to see if it could be the issue. I am not sure if this is related but fuel consumption appears to be very bad as well. I know it is not going to be great on a 1.8T sport quattro but thiught I would get more than 50 miles for a half tank!!! Do you think this is related? Oxygen sensors have been mentioned but I woukld rather not throw money at ths problem in the hope that it gets fixwed if I can possibly help it. I will check the vaccum hoses and valves (may take me a while as I have not worked on cars since the eraly 90's) is it simple to check? My level of experience pre dates cars with ECU's etc my level is things like old minis and morris minors and triumph spitfires basic but easy!!!!!

Martin.

 

MArtin take your car to autozone and have them scan it. That would be the easiest way to see excatly what problems we are dealing with. also how many miles does your car have? Audi has a tsb on the cat. If your under 80,000 or 8 years you can get your cat swapped by audi free of charge. But i would call with your vin to verify first off if the car qualifies for the recall. Cuz i know the 02 sensor trips the computer to leaning out the mixture to adjust for the bad reading. Should be simple to check the vac lines. Just go thru them slowly and kinda lightly move them a little to see if maybe the small nipples cracked. Alot of times those check valves corriide and break off at the ends. And u lose vac intermintintly cuz of the pressure lose and gain.

 

Pa4ul,

I had my car looked at by a garage today when I was having a new track rod fitted and the codes from the diagnostic are:

17705 Pressure drop between turbo and throttle valve
P1297
16684 Random Misfire 4213
16688/16686/16685/16687
16891 Idle control system rpm higher than expected P0507
17544 Fuel trim Bank 1 too lean P1136

They said that they had a look at the hoses that they could see and could find an issue. They were also going to do a pressure test but unfortunately could not get round to it so it may be done next week but really need to resolve this urgently as I am going to be reliant on my car soon for work.

Thanks

Martin.

 

At a best guess, I would say either your Turbo inlet pipe, or intake pipe have a leak. If it isn't either of those, make sure your diverter valve is functioning properly.

 

How did it go?

// Ola A.