2000 Silverado, 4.3 eng with auto. One year & over $1,000.00 later (not including parts I installed myself), I still have a "multiple intermittent mis-fire" code & the truck runs like $hit. New plugs, wires, distributor cap, rotor, cam position sensor, distributor drive gear, coil, coil hot wire, fuel filter, air filter & egr valve. The only thing I haven't changed is the ECU only because it tests OK.
Does anyone have ANY suggestions other than a gas soaked rag in the gas tank & a match. I have had two Chevrolets for the past year & both are money pits.
I am fast coming to the conclusion that GM products are a POS.

 

Have you checked compression on engine. I had a miss in a 2008 silverado. It had ate a lobe on cam only 19,000 miles. I had low compression on cylinder 4 when this happened,

 

Compression is within limits on all cylinders.
The truck has been to two Chevrolet shops with no solution from either one .....just a large bill for labor.
The problem is an intermittent miss on all cylinders at various times. Sometimes it will miss on #3 & #5 for a period of time then it will go to other cylinders & 3 & 5 will not miss. A real PIA. Everytime I drive this POS I hold my breath hoping it will get me to work. I can't afford to miss work & can't afford to keep spending money with no positive results.

 

I had a random miss on all cylinders under load I couldn't for the life of me figure out...turned out to be my cats. Not sayin it's your problem but it's the only thing you didn't list

 

This is just a complete guess but could the timing be off?

 

Does the temperature of the engine effect when the misfire happens?

 

THANKS GENTLEMEN FOR YOUR SUGGESTIONS. IT IS GREATLY APPRECIATED.
Timing is within limits (just barely).
No apparent engine temp change.
I have not checked the CATS. That will be the next thing I do.

 

I think there would be some other symptoms but it might be worth checking the ground straps and cable to the block

 

I am now $1500.00 into this POS, trying to fix a miss and it is still throwing 0300 code. Multiple random misfire. Cats have been checked since last time here, they are ok. I am completely out of ideas & very close to running out of money trying to fix this "bad mistake". Anyone have any ideas? Could the distributor be the problem. I have installed two new caps & rotor (GM) in the last 5,000 miles. New EGR (2nd one) & "engine coolant temp sensor" installed this week. Chevy dealer cannot find problem even with check engine light illuminated. HELP!

 

How much paperwork have you kept, like printout of freeze frame data? There may be a pattern? Have they looked into the CKP sensor? Was the CKP sensor ever replaced without doing a "CKP System Variation Learn" procedure? A worn crankshaft balancer can also introduce significant variations in the crankshaft rotation at certain RPM ranges.