I have a similar problem. But only when the engine is hot. If I stop at Walmart when I come back to the car, it starts and stalled right away. I have to hold the gas until the RPMs settle down. Then it drives fine but knocks whe climbing a hill. I do have a code for the MAS and the Crank Position sensor. I have both, just waiting for a sunny, warm day. Working on the street. Here is a list of ive things I have replace cause the needed it and I was Hoping for the fix.
IAC, MAP, MAS, EGR, PLUGS, AIR FILTER, PLUGS, IGN MODULE, FUEL FILTER, BELT, BATT, Cat, UPDATED ECM Program, Termostat, Cleaned TB!
Now I hear that if you replace the Crank Position Sensor you have to do a Case Relearn which is not the same as a BCM RELEARN. Was told you HAVE to go to the dealer to do it? Is that true or can it be done under my Shade Tree?
Soon as the sun comes out to play I will be under my Hood. I got all the parts. Even have muffler putty for a temp fix for my resonator. I Just need sun.

 

Hi Monte enthusiasts thought I'd post this here as it is a fairly recent topic in the forum. So I among others with Monte's am in the same predicament. Had my tranny fluid/filter replaced at the local GM deal (first mistake) then after a few wks of driving car started running poorly (erratic shifting, surging, hesitation, engine stalled/died completely twice on test runs car would just accelerate on its own idling sitting in P.) I've never had these problem before and the transmission has always shifted fine. Not blaming the certified mechanics at gm either. I did however disconnect the neg battery terminal before and had no idea of the pcm relearn. Haynes explains how to do it. Apparently if you don't, the pcm will make the car run weird thus cause my problems as of late. I just want to look further & harder before I jump to any conclusions and start replacing solenoids bc I really don't think its the tranny....yet lol. Plse let ne hear from you I hate seing my Monte sit 2004 SS Supercharged 135ks 4t65eHDtrans zzp wires delco iridium plugs K&N angel eyes headlights crystal eyes taillights everything else stock & original.

 

@misteresscoupe04intimidator: Given you mentioned at idle (I assume in park or neutral) the car is acting erratic, this should not have to do with the tranny fluid/filter change.

My thoughts are:
- Check for vacuum leaks (car running, mist starting fluid around and listen for the idle to change, if it does, try to pinpoint it a little more by spraying that fluid in the same region).
- MAF is failing (this can end in spontaneous shut downs). With the car off, unplug the MAF, start the car, it will give a CEL, but it will run on other values, working around not having a MAF. If the problem goes away, try cleaning the MAF first. If that does not solve it, replace the MAF.
- Old spark plugs and wires (or crappy BOSCH plugs). If the plugs have about 100,000 miles on them, change them. I recommend AC Delco or NGK plugs for the job (do NOT use BOSCH plugs).
- Clean the IAC on the throttle body. Too much gunk and carbon build up could be causing problems with it doing it's job properly.
- Change the fuel filter (check the air filter as well).

I would run down that list. Start from the top and work down. I hope that helps.

 

I'm with The_Maniac! If your engine is trying to DRIVE The CAR, (idling Hi) then when the trans shifts, for that split second between gears, the engine revs up instead of down, then when the trans locks into the next gear it hits Hard cause your engine is at 100 MPH But the trans is at 47mph. Follow what The_Maniac suggest. He's got a lot of MC knowledge. Hope it helps. Hate to here a MC is sitting around and not being enjoyed?