This one has me scratching my head. Car is an '87 4+3 by the way.

I jump in the car this morning to go to work, start it, and about 10 seconds after starting the SES light turns on. Shut it off and try again, SES light turns on again. The car started and settled down to the usual idle just fine, no signs of trouble from the way the engine was running. Decided not to chance it and jumped in one of my other cars and headed off for work.

So I get home tonight and pull the codes, it threw a code 32 and 42 (EGR and EST). I immediately suspect something funny as the car went from running great to throwing 2 codes simultaneously.

So I start the car, and unlike in the morning when it started and ran fine, this time it started and idled at only 500rpm or so as if the EST timing connector in the engine compartment was disconnected for setting curb idle. The SES light was on. I shut it down, checked the connector (I just set the idle the week before, thought maybe I didn't snap it back together) and it was OK. So I start it again, same deal, really low idle and a SES light.

Decided at this point to shut it off and check the EGR temp switch to see if it was closed at low temperatures (which might cause the code 42). The switch was open, so that's just fine.

I decided to pull the ECM fuse and wait a minute to reset the computer, then started it again. Like before, very low idle and an SES light. I shut it off and started it again, and this time, NO problems. Normal idle, and no SES light. I just got back from a half hour drive and never threw a code or had any problems. Got home, shut it off, waited a few minutes, started it again and no issues.

Any idea what is up? My initial suspicions are a bad bulkhead connector at the firewall, flaky connector at the ECM, or maybe an intermittent ground somewhere. I may also have an ECM going out.

Suggestions on where I should start looking? If it were a constant problem I could knock it out real quick by following the troubleshooting charts in the shop manual, but since the problem is intermittent that makes things VERY tough to track down.

Thanks,
Troy


[Modified by Banana_Z52, 7:03 PM 3/24/2004]

 

I had a leaking EGR valve which gave similar symptoms along with sometimes throwing a "Rich" code too.

You can check to see if it holds vacuum.

 

65Z01: Thanks for the idea, but my EGR solenoid and valve checked out OK.

Any other suggestions? Car made it to work today with 0 issues. We'll see if it gives me any crap on the drive home.

I'm hoping this was a one-time deal, but unfortunately the intermittent nature of the problem now has me nervous about taking the car on any long distance trips.

Troy