I have a 2000 Pontiac Montana that has made me never want to own a Pontiac again. It started with Intake Gaskets and Harmonic balancer. After fixing that problem I had a miss and shutter at around 2500 rpm I put new plugs wires ignition module and coils no fix . also replaced transmission filter and fluid along with crank shaft position sensors no fix. Engine blew up and replaced with another and it got new secondary ignition system and intake gaskets and timing chain and gears put in frame and installed still has a miss and shutter had a faulty fuel gauge and replaced gauge and pump. runs like a scalded dog when you get in it put will not shift in to overdrive it shows a miss on no particular cylinder my local Gm dealer said it was the lockup Solenoid for the trans and replaced for a small fee of $700 LOL. Still got a miss any Idea.

Van misses, sputters when shifting down to pass at about 3600 to 4000 rpm. I replaced the the entire exhaust due to a collapsed catalytic converter that broke apart and threw pieces into the muffler. Still did same thing so I borrowed an ignition module and that did not fix it. When the vehicle is cold and you put it in first gear and rev it , it cuts out at 5000 rpm as it warms up this limit reduced by 200 - 300 rpm until about 3600 rpm. I know it has a rev limiter in neutral / park, and a high speed one ( never tried that one) but instead of dropping all cylinders it sputters and backfires. New plugs / wires too, new fuel filter , fuel pressure checked and okay. Intake has been replaced also. Cruises okay and works good under light acceleration. Help!!!