Engine will not idle and misfire at high RPM?

Tiny
THUNDERPUP10
  • MEMBER
  • 2008 PONTIAC TORRENT
  • 3.4L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 103,000 MILES
Must unhook battery and drain residual charge in ECM to get it to start because ECM reads on dash; power reduced, starting disabled, service throttle, engine power reduced. This is continually changing to, misfire on cylinder #1, or other statements. I began chasing this problem a week ago. Ran perfect a week ago. I changed the Throttle Position Sensor, EGR valve, cleaned the throttle body opening, removed ECM and checked and cleaned the connections. Removed fuse box cleaned and checked connections. Checked for vacuum leaks and found none. I can get it running for 30 seconds to a minutes by reeving to 4,000 and higher but it shuts off eventually and the dash says it shut engine down. My reader clears all codes and then when I recheck it says evaporator solenoid and usually multiple codes, which are different each time, I clear and check again and it says evaporator and some new codes sometimes. It's a puzzle. Nothing consistent to go on. I'm thinking of trying a new PCV, and a new coil. Eventually I will hit on the problem but I will be homeless by then, lol. I will definitely donate. Please help desperate. I'm not too computer savvy so I'll get my son to help with adding a video, which would show what's going on much more clearly than text. Thanks again, guys, you guys are awesome! Glad I found you. PS; Also, fresh gas and injector cleaner.
and cleaned MAF. Also created new swear words never before heard by man, lol.
Sunday, April 23rd, 2023 AT 3:05 PM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,536 POSTS
I did not see the video. I would help if I could see what's going on. It does sound like the PCM is going out though due to the random and ever changing codes. I would check the PCM grounds and power inputs and all fuses. If everything seems okay clear the codes and then without starting the engine turn the key on and then read the codes again and then post them.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Here is how to change out the PCM in case you need it, you can get a preprogrammed unit by searching Google or Ebay. Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.
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Monday, April 24th, 2023 AT 12:45 PM
Tiny
THUNDERPUP10
  • MEMBER
  • 2 POSTS
Thanks Ken, the mileage is in kilometers, that 78,000 miles on it. I took the complete throttle body off today, cleaning it and maybe putting a new MAF sensor on, there was a nut missing from the MAF where it joins the throttle body. Im going to pull the coil and put a new one. While its off I'm changing the plugs in the back and front with fresh NGKs. I'll let you know when it's back together, and well see if it runs better. After that it's on to a new ECU and get it programed. P.S. Also, got a new battery.
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Monday, April 24th, 2023 AT 10:29 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,536 POSTS
Yep, that should help. Let me know how it goes.
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Wednesday, April 26th, 2023 AT 9:13 AM

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