I have an L98 TPI setup in an 86 Silverado. Last sunday was out driving it and it was running great. Shut it down, and about 5 minutes later, couldn't start it. Looked at everything, including FP relay (which was not energizing), replaced relay no change.. anyway, last nite I found corrosion in the fuse block, cleaned it out, and now the fuel pump is doing the normal, 2 seconds on, then stopping, the running when the trusck starts. So the "no start" is fixed...

NOW... after starting (which is fine, first crank, starts right up) engine stumbles then dies 5-6 seconds after starting. I can hear the fuel pump running for about 3 secs after it dies, so I'm ruling that out right now. The concern is that the engine starts to suck a LOT of air as its dying. Could this be a vacuum leak that I created while troubleshooting the original problem in the dark? I cant find any vacuum lines off. It seems odd to assume that the IAC or the MAP sensor died completely after running fine 3 days ago. I just want to know if Im missing something obvious.

Tried a different ECM to see if something was wrong with the original. Another note, I'm not looking to dump hundreds of dollars into this thing as I am selling it, in fact the sunday drive was a (uneventful) test drive, and the deal was set, and then bam, new buyer cant start his truck..

Any ideas? Thanks in advance,
Mack

 

Check the vacuum line going to the power brake booster.

 

It was the vac line on the MAP sensor. couldnt see it last nite int he dark. Starts and runs great now, thanks for the help.