new to the forum, its been helpful so far. im stuck with the lovely code p0300. its a 98 jimmy 4x4 2dr sls. code flashes at 55 and 65. ive already replaced the cap, rotor with bwd parts. ngk plugs, xact plug wires, and a bwd distributer gear. still throwing code, the truck runs great, starts up like a champs, runs perfectly fine I dont notice any kind of performance loss or any fuel problems either. like i said, it runs great but i need to get the code gone for inspection, anyone have any idea what i should try next?

 

Just cuz they're new, in this case, means they probably aren't good.... for this engine. These engines are very fussy when it comes to secondary ignition parts. AC Delco cap and rotor and AC Delco 41-993 double platinum plugs with a gap of .060" will most likely solve your P0300. Put a dab of silicone dielectric grease on each contact, inside and out, of the cap.

 

ya ive heard these engines can be very fussy from doing alot of reading in this forum. you really think by putting all these ac delco parts in that it will fix the code? and what about the wires and the distributer gear?

 

Aftermarket stuff doesn't perform well, or last, on 4.3's. Good quality tune up parts are a basic necessity for good performance. Without known good parts, you end up chasing your tail, (spending money needlessly) looking for another problem "thinking" the aftermarket parts you just installed are good.

As for the Xact wires: From the reviews I've seen, as far as quality, they are an "entry level" wire set. There have been some complaints on the fitment and longevity of them which stands to reason. These wires: Buy Autolite Professional Series Ignition Wire Set 96871 at Advance Auto Parts_____ have better specs than the AC Delco wires, at 1/3 the price.

As for the distributor gear: Kinda hard to screw that up, it either fits and works, or it doesn't. Usually what causes the gear to wear, is worn out distributor bushings. If that's the case, the distributor needs to be replaced. Replacing the gear is only a temporary band-aid. Whenever the distributor is removed and reinstalled, camshaft retard needs to be checked and adjusted using a capable scan tool. Adjustment is done by rotating the distributor slightly. The distributor hold down bracket will allow for ~14 degrees of total rotation. Camshaft retard spec is zero degrees + or - 2 degrees. If it's off, you may or may not notice a difference in performance depending on how far it's off. It can also set the P0300 DTC due to crossfire inside the distributor cap. It will not set a DTC unless it's off ~27 degrees, or more. Camshaft retard directly affects how much ignition timing advance the PCM can apply.

 

alright, thanks for all the help only thing i was wondering is if i should do all these part changes at once, or do piece by piece. as far as i know the distributer was fine when it was pulled out and had the gear replaced. im going to be doing atleast the cap, rotor, and plugs either tomorrow or friday. and possibly the wires as well. ive just sat scratching my head at my jimmy because of how good it does run and is throwing me the code.

 

See if your parts store will allow you to "upgrade" the parts to AC Delco.

 

Thanks for all the help, much appreciated. I kinda wish my truck was kinda running a little bad just so it would be easier to figure out where the problem is. I really hope the Ac Delco swaps will fix this problem. If this doesn't work, I've got no idea where to go next, let's just hope after tonight or tomorrow it will be fixed.

 

P0300 is almost always caused by faults in the secondary ignition system, (plugs, wires, cap, rotor & ignition coil). Low fuel pressure can also set P0300, so if it sets again after replacing those parts, camshaft retard, fuel pressure and leakdown are next on the list to check. Keep us posted.

 

Alright, I will keep y'all posted. I'm not going to be able to get to working on the truck till monday night or tuesday.

 

well, I just finished putting the new parts in, the Xact plug wires were nothing but ****, the ends that connected to the plugs kept snapping off the wire its self, 4 outta the 6 did that. ive also be told that my misfire could also be caused by a bad crank sensor?