HELP!!!! random misfire?

[gmoutdoorsman]

I have a 98 1500 2wd with a 4.3 v6,for almost a year now i keep getting a P0300 random misfire code. Truck runs fine,except under part throttle at highway speed and part throttle at the shift points. It shutters and surges only under part throttle and the check engine light flashes. Truck has ran fine and strong for over 100,000 miles.i cant figure out what the problem is. Has new distributor,cap,rotor,plugs,wires,ignition control module. Any ideas,fuel,compression etc??? Could uneven compression cause this issue, also ive noticed very small specs of metal in the oil. Has 205,000 miles on original engine. It runs fine when you give it a little more gas? Im starting to think its not an ignition issue. Fuel injector lines are not leaking.new fuel pump and filter also...please help

 

[oohunter04oo]

A compression test would tell you if it's in the engine. Was it doing this prior to the tune up?

 

[gmoutdoorsman]

Well i replaced the lower intake gasket last winter,noticed the distributor has some slop in it so i put a new one in. A few months later it started doing this and hasnt stopped. I want to do a compression test next. What numbers should i be looking for?

 

[gmoutdoorsman]

A compression test would tell you if it's in the engine. Was it doing this prior to the tune up?

Im afraid the small amount of metal in the oil,could be one or more of my rings,causing bad compression. Ive also noticed small amounts of oil in my upper intake near the spider injection unit. But no smoke from the exhaust?

 

[oohunter04oo]

Well i replaced the lower intake gasket last winter,noticed the distributor has some slop in it so i put a new one in. A few months later it started doing this and hasnt stopped. I want to do a compression test next. What numbers should i be looking for?

There's really no set number on the compression, but you want all the number to be pretty close to each other.

But I asked about the tune up, did you do that before the misfire or did you do it after the misfire? What brand parts did you use? These trucks are a little touchy and don't like cheap tune up parts, that's why I ask...

 

[gmoutdoorsman]

There's really no set number on the compression, but you want all the number to be pretty close to each other.

But I asked about the tune up, did you do that before the misfire or did you do it after the misfire? What brand parts did you use? These trucks are a little touchy and don't like cheap tune up parts, that's why I ask...

I replaced the distributor (duralast) a few months before the misfire started. Delco plugs and wires afterwards. Could the duralast distributor possibly be bad? Think i should buy a delco piece

 

[Stepside_fever95]

Bump. This is exactly what my 99 350 is doing, and it started after i did my lower intake gasket too.