Hello all,
My 1987 vette automatic is having problems
when I am driving the engine starts cutting out when it does this the "service engine soon" light flashes on and off and the upshift and the "D" w/circle around it starts flashing...but the tranny is shifting fine.......need help badly thanks for any info..

Bribe your nearest senior forum member with pizza and beer to get a once-over second opinion.

Jumper the ALDL pins A & B (upper right), count the flashes and come back with the codes.

Don at "Fourth Gear Inc." might be able to help....407-880-2882.......worth the call.....

I checked the codes 34, 51 bad MAP & PROM or could the PROM be causing the MAP to act funny?

87 doesn't have a MAP. Maybe you mean MAS?
When it does this, disconnect the MAS connector, and see if this clears thing up? (No fear, this action will set other codes.)
Is it a stock PROM? Has it been removed from the ECM before? i.e. Bad connection.

I reseated the prom same codes 34&51

Similar to what mine has been doing intermittently over the last few months (yes I am lazy). Except I only get a code 34 which, BTW, is low MAF. Most forum members seem to have cleared this up by replacing the MAF relays. I got a couple sitting on my bench waiting to go in.