Im gonna burn the damn thing.

[foxrider251]

Hey guys got quite the problem going on, i have a 1998 yukon 350 vortec with 270000 kms on it. from the time i bought it the thing had a slight misfire barely noticeable so naturally i did the fuel filter didnt help so a set of plugs and wires came next still didnt help, cap and rotor is where sh$t really went downhill. upon installing the cap and rotor it wouldnt start so we toyed with it and toyed with it and the rotor was 180 degrees the wrong way(facepalm) so then it ran fine...for 3 hours then it put me on the side of the road. next morning went to start it and thats when there was a full 8 cylinder misfire that literally developed overnight on its own. i have since done the fuel pump and spider injection assembly being the 2 most infamous issues with these gms and still nothing. so basically im now 1100$ in on parts 15+ hours of my own time screwing with the thing plus the 4 mechanics that have been helping me. oh and the one mechanic who owns a shop in town brought over his 7000$ mac tools scanner and found nothing wrong on the computer side of things. thanks for your time guys and any ideas are appreciated

 

[retorq]

LOL You have a slight misfire and you changed all that shit without trouble shooting it?? Your next step is a new engine bro.

 

[SunlitComet]

agreed. i think you have been going the wrong route trying to fix this issue. you need to start over with a systematic approach to trouble shooting. if you dont know the systems. i am really good at it but sometimes i have to really dig deep to find the actual cause.

 

[foxrider251]

SunLitComet, what exactly do you mean by systematic approach? i was just trying to do regular maintenance and then it exploded into this problem

 

[_Dylan_]

So, where are you at now? What is the current problem?

 

[SunlitComet]

and what maintenance were you doing when this started?

 

[Donnie Yukonie]

Well IMO it has to be an electrical Bug Obviously , since all those parts are new you have narrowed it down a little I think a new engine is Out of the question . whats the condition of the Distributor as a whole? are the teeth gone? Mechanically thats the ONLY thing I could see as being an issue My next step Personally would be looking at the ECM

 

[foxrider251]

well basically the problem now is that it will start sometimes and when it does itll run by itself for about 5 seconds, then you have to help it with the throttle. its ultimately undriveable when i tried it just about redlined on temp after a few minutes, we thought maybe the plenum gaskets but tryed spraying carb cleaner all around the plenum and no rpm jump, and as far as the distributor we havent pulled it out but it was working just fine before all this started so i cant imagine it just crapping the bed randomly. and for maintenance i was doing the spark plugs, wires, and rotor and cap

 

[_Dylan_]

the distributor could be worn and jumped time

 

[foxrider251]

i suppose, i should pull it out and take a look because if its not that it looks like everything is pointing towards ecm issues...