HELP! 1997 350 vortec p305 misfire

[bassjam]

Truck is acting as it missing and it is spark knocking. Code is reading p305 cylinder #5 misfire. I changed the plugs, wires, dist. cap, rotor button, #5 fuel injector, and still have the same problem. Any ideas out there?
Thanks, James

[MT-2500]

Got compression on that cylinder?
Is the spark plug wet or dry on no 5 cylinder?
What brand plugs?
Have you tryed switching plugs with annother cylinder to see if miss goes to another cylinder?
Any other codes?
What is the camshaft retard reading?

How is the fuel trim readings and fuel pressure?

[bassjam]

Thanks for the info. I do have compression on that cylinder. I will check the other things you said. James

[bassjam]

Got compression on the cylinder. Spark plug is dry. Switched plugs and still have the same results. Fuel trim and pressure are good. Don't know about the cam retard. I will check into that. No other codes come up.

James

[MT-2500]

If the spark plug is bone dry and cylinder is missing it is a indication injector is plugged or bad.
Does that cylinder get a injector pluse?
Is the fuel presure up to par?
Unplug MAF sensor and see if it still has a miss.
MT

[bracketshark]

My 97 5.7 had the same issue, I replaced wires plug dist. cap button checked fuel pressure seeing no results . I ended up running 2 tanks of fuel with Chevron tectron fuel additive (in the black bottle) through it and the problem went away. I use the fuel additive about once per oil change now and have had no more problems. Hope this helps.

[bassjam]

Originally Posted by bracketshark

My 97 5.7 had the same issue, I replaced wires plug dist. cap button checked fuel pressure seeing no results . I ended up running 2 tanks of fuel with Chevron tectron fuel additive (in the black bottle) through it and the problem went away. I use the fuel additive about once per oil change now and have had no more problems. Hope this helps.

I will give it a try. Thanks, James

[bassjam]

Originally Posted by bracketshark

My 97 5.7 had the same issue, I replaced wires plug dist. cap button checked fuel pressure seeing no results . I ended up running 2 tanks of fuel with Chevron tectron fuel additive (in the black bottle) through it and the problem went away. I use the fuel additive about once per oil change now and have had no more problems. Hope this helps.

After all the things I tried and nothing was seeming to help, I took a break from worrying about it. I drove it a few days and it went away. Don't know exactly what fixed it, but I am glad it's fixed. Thanks, James