Ok so i have a 2002 Audi A4 1.8t with 120k miles, the problem i am have is when i have the car in drive with my foot on the brake and at an idle the car vibrates pretty good so much that the drivers window rattles, but if i put it in neutral it goes away. it drives normal if im at a constant speed so i am thinking maby a transmission mount? what do you guys think??


thnx Paul

 

Good chance one of the engine mounts or trans mounts have failed to a point the normal vibration is being transmitted to the chassis/body. Also, double check al the exhaust mounting points, and for anything else in the powertrain that may be grounding (touching) the chassis or body. A LITTLE vibration with a 1.8 automatic in gear is normal, but not like you describe. Now if it was a B7 with a 2.0T auto, different story. Still can't believe Audi released a car that vibrates so much at idle, in gear. Not like them at all.

 

mines the opposite i vibrate worse in neutral than i do in D today i started my car had a dam flashing cel (which means car is unsafe to drive) for about 30 sec then turned off while it was flashing car vibrated like crazy and it wasnt even in drive still in park i turned my car off then back on then it ran ok got a solid cel got the codes dnt have the numbers but remeber them- Random multiple misfire i think po300 then soo on as p0301 p0302 p0303 p0304 so ALL my god dam cylinders were misfireing and a bank 1 system too lean i think p0171. and when im at a light or something car vibrates as if is choking (not getting enough of something little "coughs") checked no vac leaks and a new air filter. anyone know if a fuel pump filter or anything else fuel related could atribute to this. sorry paul didnt mean to write up this much on your thread

 

Flashing CEL means sever misfire and eventual catalyst damage. You definatley have an unmetered air leak somewhere. The 1.8L has numerous check valves which can fail to cause a lean condition at idle. Only positive way to find which one is to test each one. They should flow in one direction and not the other. Also, go over the crankcase ventilation system very carefully, especially any area you see oil vapor accumulation. There can be a crack or hole in one of the hoses or connections which are hard to find with normal methods. Highly doubtful it's a fuel supply problem. Best way is to check fuel pressure. It should be at least 35-40 psi. Fairly sure the problem is an air (vacuum) leak though. Common problem on older/higher mileage 1.8L engines. Check the PCV valve as well. I have seen the insides come apart on them occassionally. Side note: Finding the cause of P0171 on a 1.8 can cause us Audi tech's to run amok, figurativley speaking. It's usually a tedious involved process, so good luck!

 

thats what i was thinking, thnx ill check it out

 

ya thats what i thought but i took it too the dealer and they verified no vacumn leaks so i guess il have them look at it again but im thinking its fuel related because the car runs fine honestly and only at a light it will run ok then an occasional bump or vibration sometimes not at all. car runs terrible at start though after leaving it alone for a night or inactuve for 4 hours or so but after 3 min at idle its fine