I'll try to be brief-
Monday trucks running alittle rough

tuesday truck runs really rough, Idles rough whole truck shakes, accelerates rough and makes weird noise out of exhaust and you can smell it running fat.went to autozone, reads a code for bad primary, secondary coil pack in #4 cylinder, I changed the coil pack (didn't reset the computer) took it out for 5 miles ran great. Brought it home reset computer.

wednesday about 8 miles from home truck starts running like crap, throws another bad coil pack 4 code. This time the guy at autozone clears the code and the truck runs great for about 8 miles then back to same old rough running. Pulled the plug it looked fine. disconnect battery overnight.

thursday runs great until about eight miles from home then same result. I cleaned the coil pack contacts and the truck ran fine for a few miles then bad again.

What could be the problem?
I took out my chip, put in stock maf, same result ran ok for alittle bit. BTW I have denso it20's with about 18,000 miles on them.
Thanks for any responses

 

I would love to help you but you got me. I am stumped.....

TTT

Vinny

 

At the least, I'd inspect the plug under the pack, change the plug, trace the wiring from the pack to its source, the start praying.

Also, look VERY closely for leaks/drips on the pack.

Number 4 is the passenger/firewall, right? Notorious for problems from a leaking heter hose, unless I'm mistaken...

Anybody?

 

Good point Silver....Id check out that heater hose asap....

 

If thats the code its throwing it must be something to do with that. The only other thing I can think of which would give those symptoms is your IAC. Try cleaning it out with some WD-40.

-Mike