Driveability issues !!!

I have a 88 2500 350 auto 4x4 the motor was rebuilt approx 1000 mi. ago. at idle the motor seems to "surge" it starts running rough and then runs fast, back and forth. when i am driving and put my foot into it all runs fine in first gear then in second gear it bogs down and almost dies, the service engine soon light comes on then if i back off the light goes out and runs. the code i get is 33 the Map sensor, so i replaced it,same result. the EGR is good,vacume is solid and not clogged,throttle body was tuned up,new gaskets etc.it has a newer fuel pump 1 1/2 yrs,i really dont want to just start replacing sensors, ECMs,etc does anyone have any ideas or had similar problems? thanks. [i checked all my grounds as well, all good] could this be a distibutor or pick up coil problem??:banghead:

there could be a couple of possibilities.
1)the coil could be going bad.
2) would be the catalytic converter

Start with the simple stuff first, how about the fuel filter? Cat would be the next thing I would look at.

-slacker

thanks guys,it was simple after all, the coolant sensor was bad,its amazing that little @#?!%^! did what it did, many thanks for your replies!!