1988 F-150 4x4 stalling problems

[Forsaken502]

I have a 88 F-150 4x4 w/ dual tanks, a 4 spd auto and ~225,000km on it. The tranny has been switched with a replacement due to the truck being towed long distances without having the driveshaft disconnected.

When at a stoplight and driving down the road the truck runs fine, however, only sometimes, when leaving a stoplight the truck struggles, the rpm's drop, and if you don't take your foot off the gas completly, it stalls. It doesn't do this all the time and I can find no connection between the weather/temp etc.

When trying to restart, the engine cranks fine but won't fire. If you let the truck sit for about 3 or 4 min and try to start it, after considerable cranking, the truck starts and runs VERY rough (sounds like it's only running on 4 or fewer cylinders), after letting it run for about 15-30 sec it clears up and runs fine. If you let the truck sit for about 10 min instead of 3, the truck starts right up and runs fine.

If you keep the rpm's high at stoplights (holding foot on brake and touching the gas to over 1,000 rpm), it doesn't do it. But obviously, this isn't good for the tranny or the torque converter. It does it on both the front and rear tanks and the engine gets fuel when cranking (can smell gas from flooding). I'm thinking it's a ignition problem and am looking for any help. Thanks

[97chevyman]

Check your MAP sensor and the IAC sensor.