I need help with diagnostics
Thread Starter
Instructor
Joined: Apr 2008
Posts: 247
Likes: 1
From: Ohio
I need help with diagnostics
I own a 86' coupe with only 30,000 mile on her . It has always run good and today was no exception. it was a sunny and warm day here so naturally I jumped in the vette and took a fairly long ride and I didnt have any problem at cruising speed but when I was pulling into the garage I noticed it idling very erratic and surging from 1000 to 400 rpms and eventually it stalled out, I restarted it and it would not idle without surging. I tried to reset the base idle and reset the IAC and it helped alittle, atleast it would idle at 700 rpms for awhile but then it started the surging again. when it was idling I noticed a (new) noise I hadnt heard before, it sounds like a random (grinding noise) in the fuel rails, I took a screwdriver and put my ear up to it and it sounds the loudest in both sides of the fuelrail , does that sound like it makes sense to anyone?? please I could use some imput , thanx
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Base Idle doesn't change unless there's enough carbon on the inside of the throttle body to restrict flow and with that, they generally won't run.
Try it with MAF disconnected.
Take your Ignition Module to a Discounter and have it tested.
Look for vacuum leaks.
Turn off the a/c (if it's on) and see if it goes away.
Try it with MAF disconnected.
Take your Ignition Module to a Discounter and have it tested.
Look for vacuum leaks.
Turn off the a/c (if it's on) and see if it goes away.
