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Did you check the operation of the fuel injectors? The pressure could be fine but if those fuel injectors aren’t working properly it could cause misfires.
i had that code once it ended up being the spider fuel injector system there is a newer system that replaces the pop it injectors was not to hard to do either her is the part i used and here is some intructions http://www.autozone.com/autozone/parts/ … 1679_5560_. http://www.automotivehelper.com/topic559014.htm i hope this help let us know how it goes just takes alot of time and patience. good luck
How did you check for fuel pressure and did you cross reference them to GM specs for that fuel system with KOEO and KOER specs?
What brand of plugs did you use?
Did you check for vacuum leaks?
It would be nice to see the STFT and LTFT values to see what the computer is trying to compensate for here as well as seeing which cylinder is misfiring the most.
The above advice on the CPI system is also excellent. It was a poor design by GM and those poppet nozzles are not the most durable either. They have been known to also leak causing a fuel puddle build up in the intake.
Hope this helps.
Yeah, sometimes GM does weird things. It seems like that system is very problematic. If the fuel pressure is good and the pump is getting proper voltage, the injection system may be at fault. Definitely try ruling out everything first before throwing parts at it. If you still have the old plugs you might be able to tell which cylinder is having issues. Here are some links I found if you decide to upgrade the system:
http://www.gmpartsdirect.com/results.cf … pk12568332
http://www.s10forum.com/forum/f107/scpi … it-324166/
seems like a pretty straight forward job.
It would be helpful if you had an idea what cylinder may be suspect. Scan tools are great. Some of the symptoms are misfires, bad mileage, poor driveability, etc. You may have an intake gasket leak. You could try spraying some carb/brake clean near the intake port to see if you hear a change in the engine – I think Eric did a video on this. Be careful with flammable sprays and hot engine parts.
An injector cleaning service would take out the whole system and pressurize it – that will tell you if an injector is leaking. Next they fire the injectors to observe the spray pattern. You could do this yourself, but it’s dangerous since you will be shooting atomized fuel around. You would want to completely disable the ignition system and only do one injector at a time. However, it seems like when these engines start running bad – the prime suspect is the injectors.
I found a really nice video:
My thing is was the truck running bad before this happened or did it just pop up. Is there a stumble, hesitation, hard starting, etc. If the vehicle is running fine I would reset the computer and see if it pops up again, reason being is it is a general misfire code. I believe if it has a last number like P0301 then the 1 will indicate what cylinder had the misfire, for example it would be cylinder 1. Now I said to reset if you have no other derivability issues with the truck. If there are other issues then we may need to address them first. Good luck.
well when i hit the gas pedal it had slow response and i also cleaned the throttle body changed the fuel filter and pcv vavle.
DTC for which Freeze Frame was StoredP0300Fuel System 1 StatusOpen LoopFuel System 2 StatusOpen LoopCalculated LOAD Value3.53 %Engine Coolant Temp91.40
Since that is a general misfire code you might want to do a power balance test to see if you can find out if it’s a particular cylinder that is the problem, here is a video on how to do the test. If you find a particular cylinder that is at fault then the next step would be to determine if it’s a fuel or ignition problem.
well heres what going on when i go to take off it has slow response but when i get it up to highway speeds cant feel the roughness in it the roughness is only at idle or taking off i did the power balance test all of them when down when i tried them
It’s interesting that the code as set when the idle was closed but you have a performance issue when you take off, it also looks like it might be running rich. Just for the heck of it pull the vacuum line off of the fuel pressure regulator to see if any fuel comes out if it does then it needs to be replaced.
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