I have noticed that in my 98 A4 1.8T that at idle u can hear a tick coming from the passenger side of the vehicle toward the motor. it is rather quiet and cannot be heard when rpms are any higher than idle, it is also inconsistent, it will be really slow then with out any thing to provoke it, it will speed up to a fast pace. revving the car does not seem to have any affect on its speed or consistency, also it will just go way and come back a min later...i find this strange and am rather worried about what I should do or be looking for. help plz?

 

there's been a couple threads about this recently. Search for engine tick and see what you find.

 

Sounds like valve tick. If that's what it is, it's normal.

 

Sounds like you're experiencing the same thing I had. But just last night, I discovered that my tick was an exhaust leak.

Last night on my way home, the catalytic converter completely separated from the flange that connects it to the turbo.

With yours being inconsistent and randomly speeding up without revving the engine, I'm betting it's an exhaust leak.

 

so I have a potential valve tick and an exhaust leak? how would i check for the exhaust leak?

 

Look and listen very closely. Very carefully feel around for any air escaping the joints around the connections on both ends of the catalytic converter; at the turbo and at the downpipe.

And yes, valve ticks are common based on the research I've done while trying to discover my car's ticking issue. It very well could be a valve, but I find it hard to believe that it's a valve with the ticking fluctuating in frequency without revving the engine.

 

hmm, i try that, and I felt no escaping air anywhere. I'd like tot think it's a valve tick seeing as it's not a large issue. It is weird though, can a ticking valve stop and start ticking over the duration of the motor running? on and off so to say?