ok i have an 00' silverado with the 5.3 and 75k miles on it. i just replace the fuel filter, air filter, motor oil, plugs and some other stuff. the problem is that if i put 87 oct. in my truck, the thing knocks like you wouldnt believe. so i tried premium and the knocking was GREATLY reduced. it still knocks if i punch it going up a streep hill though. so what do u guys think? i heard mayme timing problems. oh yea, forgot to say, my computer has been acting weird lately and sometimes when i start the truck it wont idle so i have to turn the ignition off and start the truck again to get it to idle.

 

I would replace the PCM, this gives you a reason to go with an aftermarket tune should be about 150 and they send you a new pcm.

 

You could try cleaning the throttle body and doing a top end service with a product like Seafoam (you get it at NAPA and the directions are right on the can). If the combustion chambers are full of carbon, it will contribute to the knock/ping you're describing. Also, if the throttle body and IAC are gummed up, that could contribute to the stalling you describe.

 

The winer blend gas I am sure isnt helping.

peace
Hog

 

ok i used some sea foam but i still have a half a tank of gas till i fill it full of 87. if it still knocks, any other advice?

 

buy some residue free electrical contact cleaner and spray the mass airflow sensor down. thats probably your problem

while your at it put your old plugs back in and run a can of seafoam through the gas and run 1/2 can of foam through the top end via the brake booster vacume line. just unhook the line rev the truck to about 2K rpm and SLOWLY suck the foam out of a cup into the intake. turn off the truck for 5-7 minutes, start it up and go driving until all of the smoke is gone. put your new plugs back in afterwards because the foam can foul em out or wear away at them pretty good.

if your near a oilchange you can run seafoam through your crankcase too but ive never done it and havent heard of anyone else doing it...not sure about how much to put in there but you just put in what the bottle says, let it idle for 5-7 minutes and immediatly drain the oil afterwards. seafoam rocks

 

It's called high mileage. May go away with a valvetrain refresh. A buddy of mine has the same problem. Been running premium for about 30-40k now. He has almost 140k on his truck.

I don't think it's a timing problem. Sounds normal for higher mileage vehicles to me. Your just hit the area a little earlier than most.

 

ok i just f***ing replaced my plugs but thanks

 

trying completely disconnecting the pcm. steps I did;

1. disconnect neg battery cable
2. remove pcm COMPLETELY
3. pump brakes a few times
4.install pcm
5. MAKE sure each pin is pushed in
6. reconnect battery
7. start and hope for the best.

This is for the starting problem I dunno if it will ehlp the pinging, that would have to be changed with software.