Hi everyone, i've just bought an 02 A4 1.9 TDI manual. I've had it for a couple of weeks any it's found it to be a great solid drive and nice car but am wondering if my new motor could be a lemon.

The history on the car is the fanbelt slipped which bent a valve or 2. This was then repaired by an audi mechanic who was the previous owners friend and done as a foreigner on the weekend. Not sure exactly what was replaced(think head and valves) but will be finding out when I drop it back to get the boot mechanism fixed soon.

When I drove it on the test drive and found no problems with starting(first turn of the key from cold), it ran totally smooth with good power on all gears etc....

Afew days ago I was sitting in traffic for a while getting through some roadworks and heard a single missfire followed afew minutes later 1 single but loud-ish Knock noise from the engine. After this the engine ran as before and has been running with no problems ever since. the only difference is a high pitch metallic rattling sound coming from the engine between 1500 and 2000 revs. The sound is so quiet that having the fan on half strength or travelling over 40mph drownds out the noise. Thinking about it it could of been there all the time as you have to listen out for it.

Another thing is slight vibration or shudder that goes through the car when idling. I've noticed this happening before the missfire above. This slight shudder or shake goes through the car randomly and will go for 2 seconds then stop for 4 then start again but always varies and only when the engine is warm.

Has anyone had similar symptoms as this and offer any suggestions as to what is happening please. Cheers Daniel.

 

backfire, engine runs good, weird noise only during selct rpms?

exhaust leak. Check for dark black soot? I dont know how to spell it, but the super black stuff that a fire makes =]

 

lol cheers, i'll have a look when i get time. Would it more likely be a leak at the manifold/cat to cause a misfire or would it be further back?

 

depends on where you felt you heard the noise come from. My chevelle popped at the first exhaust flange. Scared the hell outta me. Wasnt till the next day i realized that the gasket was burnt to a crisp giving me some sweet noises.

 

Id, check the harmonic balancer and exhause for leaks/damage, your're gunna want to get in there good and maybe give it a scan quick.
even if there is no CEL
Codes can be stealthy