my astro runs rough with any load on the engine?
 

I have a 1988 chevy astro with a rebuilt engine it runs good untill i put any kind of load on the engine then it begins to run rough and viberates and acts like it wants to die, it will do this for about 1 minute and then returns to normal again, it will do this when i put on the brakes , turn on a/c, turn the steering wheel to far, and when i first put it in gear, . can anyone please help? it is a 6 cyl with automatic trans pwr steering pwr brakes i think it is the 4.8? liter engine with fuel injection. thank you Mike.

RE: my astro runs rough with any load on the engine?
 

no check engine light?..sounds like a misfire...astro's were bad about the coil wire grounding out against the tinfoil lining of the engine cover