Hesitation/backfire at WOT
 

OK, hopefully my last problem - thanks for all of the past help.

If I am at a standstill in DRIVE and punch the throttle, there is a 1-2 second "hesitation/lag" and it almost seems like the truck wants to stall, then it finally gets going. 25% of the time it will even backfire once (not sure if it is backfiring through the carb or the tailpipe but I hear the pop).

Could someone give me a list of things to check please?

Thanks.

RE: Hesitation/backfire at WOT
 

I'd check the spark plug wires & coil wire first. Poor wires with spark pulses jumping all over the place will cause hesitation & misfire/backfiring. It could be a great "light show" underneath the hood if you check it at night.

RE: Hesitation/backfire at WOT
 

Well, I just changed the plugs and put a coil in it about a month ago. I did not change the wires, but they appear to be somewhat new and in good condition.

Remember, it only backfires and hesitates at WOT and only for a second or two, then it runs great.

RE: Hesitation/backfire at WOT
 

backfire is typically due to timing, ignition timing or cam to crank timing.
I'd guess your timing chain has some slack in it, and if you keep romping on the go peddle you'll find out how much work it is to replace. Either that or you will break your distributor gear and have fun pulling that out of the oil pan. [8D]

RE: Hesitation/backfire at WOT
 

I figured it out.
It ended up being 2 things. The Throttle Position Sensor was not working properly in the upper end of the rotation and I took the throttle body off and WOW, it appeares there was a fire at one point. The gasket was burned and several of the vacuum line passages on the underside of the throttle body were COMPLETELY caked with crud. It took hours soaking in carb cleaner and a pick and wire brush to get it cleaned out. This was also effecting my rough wandering idle because the IAC value was also not only covered in crud, but the passageway it used to sample the air was nearly completely blocked as well.

Thanks again for the help.