left side engine miss

[arkhogs2011]

I have done all I can now I'm going to turn to you guys. have a 350 Vortec in a 96 GMC. I bought this truck about 6 months ago with no problems the engine is a JEGS motor with roughly 17k on it. I got some non ethanol fuel from an 'unknown' gas station and started to have an awful miss at idle. ran injector cleaner through it for about a week nothing helped still soaked plugs 2, 4 , 6, 8, were my problem children. Broke down pulled injectors out and replaced them put cab rotor and plugs in while I was there. Guess what same problem! But this has brought my problem down to only cylinder number 4. Did a compression check every cylinder passed moved on to an intake gasket sprayed brake clean around everywhere there could be a leak and nothing. Now we are to the point that it only does this when I start it hot or cold 90% of the time If I drive it just about any distance this will mostly go away with me only noticing it because I am now looking for it. Plenty of spark and fuel that is all going out of the tail pipe. Also now my only code is an o2 sensor which just started I would assume from all of my hard earn money going out the tail pipe.

 

Any help or ideas is much appreciated!

[Swimmer8366]

O2 would cause it to dump fuel.

 

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[Logan Lanfear]

I would check O2 sensor and also fuel pump pressure. Incorrect pressure coming from the fuel pump can create a mishap with the injectors. Same thing happened to my '98 turned out the pump was pushing around 100 PSI and the rest of the system didn't like it.

[arkhogs2011]

Okay thanks I will check the fuel pressure and see if the o2 has voltage.