backfiring at high rpm

[Big Country]

When traveling at high RPM (i.e. On the highway) my truck starts to backfire and the RPMs start going haywire, everywhere around the gauge and then i slow down to like 20 for a while and then start driving again, and it's fine for a while, and then does it again. Anyone know what thsi is. I judt fixed an exhaust leak at teh ****** where the pipe meets the header but both pipes seem to be pushing the same amount of air.

any thoughts????

Thanks!

 

[1982 bronco lifter]

timing chain is off

 

[gnarly_bronco_kid]

When traveling at high RPM (i.e. On the highway) my truck starts to backfire and the RPMs start going haywire, everywhere around the gauge and then i slow down to like 20 for a while and then start driving again, and it's fine for a while, and then does it again. Anyone know what thsi is. I judt fixed an exhaust leak at teh ****** where the pipe meets the header but both pipes seem to be pushing the same amount of air.

any thoughts????

Thanks!

Yeah check your timing, and also you need to check your spark plug wires. when they get worn through the rubber and to the core they start to arch over to whatever they're rubbing on. I wouldn't drive your truck untill you get this figured out because backfire is a great amount of wear and tear on everything. I've seen a backfire blow hole in a muffler 10" wide.

 

[Seabronc]

Please only post in one forum, thanks. Ditto on the timing and possibly the timing chain.

>-

 

[rebelyelltex]

ive had this problem before as well and for me it was the timing chain. good luck man!

 

[Yardape]

If timing chain passes inspection, check distributor cap, you could have an electrical storm in there. Should be able to solve with new cap and rotor.

 

[Big Country]

so this possible timing problem would not effect the truck running in any other way except highway rpm?