Questions and Answers

Eagle Vision Has A Slight Rough Idle Q. My car is a: 1993 Eagle Vision TSI 3.5 liter V-6 engine Automatic transmission 130,000 miles PS, A/C, cruise control

Plugs, PCV and air filter were recently replaced. Spark plug wires were replaced last year. The idle is a bit rough. With the car in drive as I start to ease up on the brake and the car starts to move the roughness is more pronounced. If it gets into a full roll or if I press on the gas, the roughness disappears. The car runs fine after that; no problem with acceleration. What could be the source of the problem?

Thanks,
Frank

A. I think a Throttle body cleaning will fix this problem. Under normal or severe operating conditions, it is possible for the throttle body to build deposits in the air flow area near the PCV inlet, and/or near the Automatic Idle Speed (AIS) inlet. These deposits can cause driveability problems that may or may not appear as a fault code in diagnosis.

Ideally, the best way to clean them, you have two, is to remove them and give them a good cleaning with carburetor cleaner. If removing them is beyond your skills, or just too much work, they can be cleaned in place.

I wrote an article DIY: Cleaning Throttle Bodies that will help you do the job.