Bp SWAP 92 FIVE SPEED

[shadetree]

Completed a bp swap for a buddy . Car has a very randem idle drop fit that it wants to drop and then shut off . Sometimes it will take a couple restarts to get it to stay running .
Ive cleaned with seafoam and went through timing and reset idle screw . The problem has made the owner ask about switching back to the stock engine its getting that bad . The jy engine had 80,000 miles and will run great when it wants to . I cked vac lines for clogs and went through all the normal repair things i could think of , so any help would be great !

[shadetree]

Car has been together and running for about six months. At any random time it will drop down and not idle . We changed plugs , wires, cap , fuel filter , air filter was new when built . The engine was in a warehouse for eight years on a shelf so i went through all the vac hoses before i installed it and made sure everything was clean and ready . There are no codes that stay in the ecm long enuf to read but the engine light will flash on from time to time .

[FestYboy]

intake tube cracks? look for false air. wiggle test the VAF connector. does it have the intake box that goes after the VAF?

[BUSTIVA]

Definitely sounds like unmetered air is getting into the motor somehow.

[Aaronbrook37]

Definitely sounds like unmetered air is getting into the motor somehow.

Agreed! Who knows... may be a dead gasket or a couple of loose bolts here and there.

[Damkid]

If its an intermittent problem, could it be in the IAC?

[FeistyFesti]

Maybe one of the pins on the VAF connector could be corroded or loose.

[blkfordsedan]

All are good suggestions. The only point I would make is the problem is something simple like a loose hose, electrical connection, etc.. Even though those can be the worst things to try and track down, you can reassure the owner that switching back to the stock motor may not (and probably will not) make any difference.