Stumble start and roaming idle
Thread Starter
Launching!
Joined: Feb 2010
Posts: 246
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From: Houston
Stumble start and roaming idle Hi friends,
After a fresh rebuild I am seeing about an 8 second crank to start while cold, instant when hot. The car likes to idle at about 1500 when the car is in motion, but will drift down to 1000 when at a stop. Every so often at stop, the car will drop idle to 500 or so and struggle to stay running, but this is rare. I also hear an occasional backfire at high end.
Car is freshly rebuilt 95 Z28 m6 with LE2 H/C , new AC Delco Opti, MSD wires, new ICM and Coil. On first few weeks, car would start up instantaneously and had a stable idle, but has slowly deteriated in the last few months.
What are the most likely culprits and where should I begin my diagnosis?
After a fresh rebuild I am seeing about an 8 second crank to start while cold, instant when hot. The car likes to idle at about 1500 when the car is in motion, but will drift down to 1000 when at a stop. Every so often at stop, the car will drop idle to 500 or so and struggle to stay running, but this is rare. I also hear an occasional backfire at high end.
Car is freshly rebuilt 95 Z28 m6 with LE2 H/C , new AC Delco Opti, MSD wires, new ICM and Coil. On first few weeks, car would start up instantaneously and had a stable idle, but has slowly deteriated in the last few months.
What are the most likely culprits and where should I begin my diagnosis?
Your idling issues are likely caused by your tb and or your iac sensor. Id first pull the iac sensor out and inspect if its all carboned up causing it to stick. Id also count on the fact your IAC counts are likely high you might need to look up the drill mod to bring down your counts which will help with your idle. All aftermarket tbs have this issue with cammed engines. As for your starting issue im not totally sure mine does the same thing cold crank it takes a bit to get going and warm its usually first crack it fires.
