The "accelerator pump" and backfiring issue solved. Might have been the ignition module or excessive rust under the cap or both. I over-torqued the #6 screw trying to remove the module (SNAP) and ended up replacing the distributor.
No pic's or part #'s. I am relying on memory but my 6.2 had a vacuum pump where the "distributor" is on a gasser and the a/c compressor went on the passenger side in front of the head.
My local FLAPS comes up with a switch for r12, nothing specifies 134a. The r12 switch has 6551828 stamped on it, will it work on a retrofit r4 compressor using 134a?
Thanks for the dorman number.
I am converting my 1990 GMT400 from r12 to 134a. Does anyone have the part numbers for the pressure switches of the r4 compressor and dryer?
Thanks,
Rick