Engine

Idle Roughness - Progressively Worse

Several weeks ago I posted that my 86.5 wouldn't idle. Finally got the problem fixed and wanted to thank a few people and let everyone know what the problem was. The idle problem progressed into a total loss of power if anymore than about a 1/2 inch of throttle was given. Also some black smoke and fouled plugs.

Thanks to everyone that offered advice. The prize for long-distance, diagnosis of my problem via email goes to Vince Yu. It turned out to be the air mass sensor. It ran exactly the same whether the AMS was plugged in or not, so I figure the FI computer just wasn't getting any info from the sensor. Thanks to Jim at Devek for mounting my AMS on one of his cars and testing it. What service!

Jim also recommended the Bosche 4477 4 prong plantnum plugs and they are awesome. The car is an absolute screamer now. It has more power than it ever has in the 4 years I've owned it. Can't wait for some cool weather boost. I replaced the O2 sensor, plugs, AMS, and added a K&N air filter, so I'm not sure which is making the car so much faster, but I think the plugs have alot to do with it. 2nd gear scratches on dry pavement are common now and used to be very rare. The O2 sensor definately gave me a smoother idle.

So glad to be back on the road....

Don Carter
86.5 928S Auto Meteor Metalic
Houston, TX