Another P0300 code question

[bracketshark]

1997 1500 silverado. Ok, now that my interior lights are repaired more serious stuff needs attention. I just bought this truck and immediatly had to put a intake gasket on it. Now that I've finally able to drive it it has random misfire (code p0300) between 40 to 55 mph, but its not all of the time. I did a forum search and what I gather is, it's most likly is a fuel injector problem, judging from others experiance. When I went to my local dealer for pricing on the injector cleaning they almost insisted it was plugs and wires. This truck has had wires put on it at sometime before I got it they look good no white marks from arcing and the plugs are some brand of platnums, its also got 154,000 miles on it, burns no oil and now leaks no more water. Do you think I'll be wasting money to replace the plugs and wires again? I want to fix it I just don't want to throw parts at it. Suggestions appreciated

[2000CAYukon]

Do you know what brand of platinums are in your truck? I have heard of so many problems with the Bosch plugs. I only run AC Delco Platinums and never had any problems. It may not hurt to pull one plug and take a look at it. If it is Bosch, I would recommend replacing them with AC Delco.

//2000CAYukon

[SpitAndDirt]

154,000 miles? Cap and Rotor get replaced? Why does everyone forget that our trucks still have a cap and rotor?

[bracketshark]

I should have mentioned cap and rotor already replaced, I will check the plug type tommorrow. Thanks for the suggestions, any more?

[bad68chev]

What kind of wires? Are they factory? I put aftermarket wires on mine (autozone) and they started misfiring after only 18,000 miles..you can check them by misting them with a spray bottle while the engine is running. I would reccomend either factory or MSD wires, thats what I run and I haven't had a problem since switching from the cheapie autozone wires. as far as plugs, I would reccomend Factory.

[bracketshark]

My msd wires were delivered today, and there are Bosh plugs in the motor. I'll get a set of AC delcos and see if there is any differance.

[markqc]

If you notice the problem more in damp conditons/fog I would change the cap and rotor. I was told by a GM mechanic that the cap & rotor are a cheap design and need to be replaced a little more often. I have had a similar problem and the cap and rotor seemed to fix it. I had to replace them once after about 15 months and about 23KM but I think every two years is probably normal.

Good luck,
Mark

[bracketshark]

damp or dry no differance I'm going to replace the distributor also, Ive got a spare. thanks

[bad68chev]

If you replace the distributor, make sure you buy a GM factory one. Ive seen and heard alot of problems with aftermarket distributors. My friend put a NAPA one on his Suburban, every time he turned his steering wheel at a stop the vehicle would die from the extra load. (the original one had alot of play in the shaft causing a misfire but wouldn't die). He yanked it out and put a GM distributor in it and now it runs great. MSD and Accell make the best distributor caps, they have brass terminals which conduct alot better than the factory (I think factory are aluminum).

[bracketshark]

I changed the plugs to platnum AC's tonight, that didn't help it might be worse now than before. I'll install the new wires tommorrow night.