I recently picked up a 2000 GMC Jimmy. Shortly after I bought it, it threw a P0304 code. It has almost 170k on it and not knowing its history I figured I'd give it a tune up. I replaced cap,rotor, plugs and wires all AC Delco. I had a new coil on my 99 blazer that I'm parting out so I figured why not and swapped it. It ran ok for a day. P0304 came back. I had a injector spider on my blazer that was only about a year old and I knew was good so I swapped it as well. It has a miss at idle the miss goes away under acceleration. You can watch the miss go away when I have it on the scanner. Fuel pressure is 55 PSI idling 51 PSI under a load 60 PSI before cranking. Fuel leak down test it held pressure for 15 mins with maybe 1 PSI drop. I've checked and rechecked the plugs and wires. I'm stuck, this is the first one I've had miss at idle but smooth out under acceleration and has good power. I read about stuck valves it would run bad all the time if it was that. There is no hard start issue either it fires right up. Any ideas am I missing something?

 

Hey man I know this is old but did you find our what the problem is I have a 2000 that's doing the same the I have 160 miles sounds just like mine

 

1. Any other codes?
2. Any recent work?
3. Can you monitor live data with a scanner?

George

 

No recent work I se he said it was the spider injection it has spark I think its the fuel side