ZR-1 Down =(

[We Gone]

Remove the two black torx screws from the silver cover at the rear, your map sensor is under it and also held on by the two screws. (be careful not to drop them) As you lift it you will find a vacuum line hooked to the bottom, it may also be oil soaked and fit lose if you can put a small tie wrap on it. Hope its your issue if not check the lines under the front of the plenum just behind the throttle body drivers side.

[Okiedoke]

Originally Posted by Dmod81

It would be that black plastic line just to the lower right of the green connector in your first picture. It can be kind of hard to reach and reconnect sometimes.

I hope this is it!! I put my finger in there to feel around. The bottom right end of the line is disconnected and had oil coming out of it. Let me see if I can feel around some more and try to get it connected.

[We Gone]

Here is what the underside looks like, if the vacuum line is off that's most likely your issue.

[Okiedoke]

Originally Posted by gbrtng

It probably backfired and blew the MAP hose off at the back of the plenum. Check at the rear of the round thingy for a loose hose. Reconnect and the CEL will go away by itself.

Never would have guessed there would be a loose plastic hose that slips into a hole completely unsecured, but there it is. Guess the stiffness of the plastic hose helps keeps it in there most of the time. As soon as I put it back in, she fired right up and idled smoothly. Do I need to figure out why it backfired or is it normal for that to happen once in a while?

Thanks a bunch to everyone for your help! The knowledge of folks on here is just amazing! Man, was I sweating!

[gbrtng]

Originally Posted by Okiedoke

Never would have guessed there would be a loose plastic hose that slips into a hole completely unsecured, but there it is. Guess the stiffness of the plastic hose helps keeps it in there most of the time. As soon as I put it back in, she fired right up and idled smoothly. Do I need to figure out why it backfired or is it normal for that to happen once in a while?

My 91 sneezes every so often and blows the MAP hose off. Some folks secure the hose but my best bet is to leave it loose so something harder to fix doesn't split/break/fail. Some claim that releasing the key from cranking too early causes a backfire - not on mine. It's just haunted ...