Rough Idle

[cauchy]

Greetings All:

2006 GTI, last summer ran rough intermittently, fixed with new plug coil. Always starts, never cuts out. This year, great high end, much better than last year, but.......

From a cold start on a typical ride, I run 5 minutes out of the no wake zone, idles 1800 rpm+/-, just fine. Then slow acceleration up to 7000 rpm, no problems, smooth as silk. After the initial run-up just described, runs great smooth and full power over 3000 rpm, but idling, below 3000 pm is rough, especially after warm start.

Will drop in new plugs and have a new plug coil on order. Still under warranty - which was an issue last year as I had the 100 hr service performed out of network but that is another story, BRP gave me an assurance in writing that warranty was not voided so will initiate troubleshooting at dealership this time....

That said, any suggestions/troubleshooting I can do myself? I can live with the problem right now. 132 hours.

cauchy

 

[Dennis]

Bad idle

Why did you order a new plug coil? Your 4TEC engine has 3 coils. Replacing your spark plugs is the correct thing to do first (DCPR8E).

DAWG

 

[cauchy]

I have a new set of plugs ready to go in first. If one coil could deteriorate, so could two. They are problematic and may not show either physical deterioration or faulty ohmmeter readings. The shop manual says that the only way they could be diagnosed if they fail under load is to pull and replace. I found my faulty coil when I pulled the plug (stern) and discovered it was MUCH cooler than the other two.

So, plugs first, then the coil. If the other two are okay, I will have insurance.