Ruff cold idle LT1 fixed
Thread Starter
Racer
Joined: Sep 2011
Posts: 462
Likes: 30
From: Riverside California
Ruff cold idle LT1 fixed
Hi guys....been hunting for a slight surge mostly when cold in drive at a stop. Found a couple of broken vacuum lines in the cruise control line behind the battery. No change.
The fix..unplugged the IAC connector to see if there was any change, idle went to 1500rpm and held steady. Stopped the engine plugged in connector and did a IAC reset.
Throttle pedal slightly open, started engine for 5 seconds, engine off for 10 seconds, restarted, bingo smooth as a babies bun. FSM did its magic once again.
93 LT1
The fix..unplugged the IAC connector to see if there was any change, idle went to 1500rpm and held steady. Stopped the engine plugged in connector and did a IAC reset.
Throttle pedal slightly open, started engine for 5 seconds, engine off for 10 seconds, restarted, bingo smooth as a babies bun. FSM did its magic once again.
93 LT1
Thread Starter
Racer
Joined: Sep 2011
Posts: 462
Likes: 30
From: Riverside California
Ruff idle fixed- not
Hi guys....been hunting for a slight surge mostly when cold in drive at a stop. Found a couple of broken vacuum lines in the cruise control line behind the battery. No change.
The fix..unplugged the IAC connector to see if there was any change, idle went to 1500rpm and held steady. Stopped the engine plugged in connector and did a IAC reset.
Throttle pedal slightly open, started engine for 5 seconds, engine off for 10 seconds, restarted, bingo smooth as a babies bun. FSM did its magic once again.
93 LT1
The fix..unplugged the IAC connector to see if there was any change, idle went to 1500rpm and held steady. Stopped the engine plugged in connector and did a IAC reset.
Throttle pedal slightly open, started engine for 5 seconds, engine off for 10 seconds, restarted, bingo smooth as a babies bun. FSM did its magic once again.
93 LT1
Safety Car
Joined: Aug 2013
Posts: 4,427
Likes: 603
From: Minneapolis Mn
I was having some idle and low rpm issues on my 86 and it kept coming back to the IAC though codes pointed elsewhere. I'd bought another IAC but hadn't replaced it yet and was checking again one day. I was irritated and happened to have a plastic faced hammer with me at the time. I gave the IAC 3 or 4 so-so raps with the hammer and low and behold the idle issues went away and have not returned. I've also spent some time cleaning grounds etc on the car what may have helped but no way to tell for sure.
In my case if it was cold out, start up and go a few blocks then it would barely run. I always nursed it home to the garage. After 5-15 minutes, restart and it would run perfect, did not get codes every time though the SES light would come on most of the times when it happened but went away once back in the garage. Didn't happen every time, but when it did it was painful. IIRC the code I got occasionally with the SES was 43, it indicated a ECM failure. Everything else seemed to check out, so wasn't sure that was truly the cause. It's been a long time since it last happened and hopefully will not come back.
In my case if it was cold out, start up and go a few blocks then it would barely run. I always nursed it home to the garage. After 5-15 minutes, restart and it would run perfect, did not get codes every time though the SES light would come on most of the times when it happened but went away once back in the garage. Didn't happen every time, but when it did it was painful. IIRC the code I got occasionally with the SES was 43, it indicated a ECM failure. Everything else seemed to check out, so wasn't sure that was truly the cause. It's been a long time since it last happened and hopefully will not come back.
Burning Brakes
Joined: Jan 2007
Posts: 1,170
Likes: 86
Hi guys....been hunting for a slight surge mostly when cold in drive at a stop. Found a couple of broken vacuum lines in the cruise control line behind the battery. No change.
The fix..unplugged the IAC connector to see if there was any change, idle went to 1500rpm and held steady. Stopped the engine plugged in connector and did a IAC reset.
Throttle pedal slightly open, started engine for 5 seconds, engine off for 10 seconds, restarted, bingo smooth as a babies bun. FSM did its magic once again.
93 LT1
The fix..unplugged the IAC connector to see if there was any change, idle went to 1500rpm and held steady. Stopped the engine plugged in connector and did a IAC reset.
Throttle pedal slightly open, started engine for 5 seconds, engine off for 10 seconds, restarted, bingo smooth as a babies bun. FSM did its magic once again.
93 LT1
Thread Starter
Racer
Joined: Sep 2011
Posts: 462
Likes: 30
From: Riverside California
