im stumped please help (exhaust pop)

[CHEVYMATT]

i have my truck running great but when im cruising above 3000 and i let out it will back fire thru exhaust about 3-5 sec after i let off gas .if i wack first and second then let off its fine but if i stay in it until third gear then when i let off it will pop hard out ehaust. my timings at 32 and i had it at 35 my plugs look good and are gapped at 32 . my valves are lashed at about 16-18 when hot .ive upped jets and ,lowered jets but still has load bang . it started after first time at track that i can remember . any help would be greatful. thanks for all the help on previous threads.

[bjuice]

check your exhaust manifold gaskets and header or exhaust/donut gaskets where it ties into your exhaust pipes underneath your car....this popping sound is typical of cool air being sucked into the exhaust when you let off the gas in return you get a popping sound ..the cool air interuppts the burning off of exhaust gases...


ps..also look over your manifold's or headers and all your exhaust tubing for pin holes..normally it will be toward the motor when this happens...

hope this is your problm..

Brian

[CHEVYMATT]

well this is in a s10 and the headers are piece togeather so there is some leaks here and there . i'll have to look it over thank you

[cepx111]

Well that last statement said it all, there's noway your gonna getaway from the engine backfiring with all those leaks , scrap the make shift headers and buy some new ones or take your time and weld up all your leaks.
Hope this helps.

[CHEVYMATT]

the headers are full lenth hooker super comp but they are slip connector because they wrap the around the frame on both sides. i will though try to wrap them with some header wrap. thanks guys

[cepx111]

Yeah those slip together headers do tend to leak, I found that the fiberglass muffler tape works really well, its kinda sticky so it's tricky to get in tight places but if you can get it in there and wrap it up good, when its gets hot it will melt and bond to the header and seal up all those pesky leaks around the slip joints.