02 GMC Envoy engine trouble. Help

[quote=”ramman1221101″ post=153116]My Girlfriend has this GMC Envoy has a 4.2 in it. Im getting a P0300 random miss, P0340 Camshaft sensor, P1481 Cooling fan? From info i gather it was bought running ruff for cheap and it was parked and never touched again. I havent went in and did any real daig to it yet. but ive never messed with this motor before i dont know where to even start. Any idea as to what this might be?[/quote]

Hello ram_man! Please tell BITOG that GHT says a friendly Hello.. and looks forward to partaking on there soon (that’s not up for debate, lol, I’m on there.)

As to the vehicle. Have a 2003 Envoy. XL, but the 4.2.. Same exact thing, especially 2002-2003 range (first and second year,) and I had P0300.

As you know, P0300 is “Random multiple misfire.” Happens usually after you crack a coil Seafoaming it, as I have done at least twice, possibly three times. Where to start: Get a coil. Best one is the Delphi unit, let me get that link for you: http://www.amazon.com/ACDelco-12568062-Original-Equipment-Ignition/dp/B0013G03I4/ref=sr_1_1?s=automotive&ie=UTF8&qid=1448875041&sr=1-1&keywords=ACDelco+12568062+GM+Original+Equipment+Ignition+Control+Module ACDelco 12568062 GM Original Equipment Ignition Control Module – That is the one.

When you get either just one (as I did.. I actually needed two one time, the P0300 time) Or all six.. You need to “move” the coils, to see if you can isolate the misfire to a particular cylinder. It will change from P0301-P0306. The REAL bootleg way: Pull a wire while it’s running, listen for a change. If the engine idles down, it is working as it is supposed to, and only running on technically 4 cylinders for the briefest of moments the plug is pulled, since there is still likely a dead coil – the prime cause of a P0300 – and the one you pulled for about 5 seconds, to listen.) If you pull it and there is NO change: That’s your coil.

Once you find that coil. REMEMBER WHICH ONE IT IS.. They really ARE identical, and can get confused in about 2 seconds, despite your best efforts, so mark it clearly.. and Put it on ANOTHER cylinder, and create the P0303, P0305.. Literally pick one. The three in the middle are the easiest to get to, though I had no real problem getting to any, even the one in the back… A short extension is critical there, but after that it’s do-able.

Clean up everything as you take it apart and you should have P0300 licked..

Just about guarantee you it’s a dead coil.

Check Engine light flashes on that one and it won’t let you set the cruise, right? That’s because I thought my engine was DONE FOR after the Seafoaming when that happened. But I fixed it. Twice, as I did it twice. Once cracked one coil, once cracked two…

Salutations. – GHT

(Also, please share this post with BITOG if you like, since they, especially that Bandito440 guy, seems to think I’m jus”doing this for fun.” I DO have the ability to be helpful.)