408 popping/ backfire under load
#1
408 popping/ backfire under load
Ok so here's the thing. I have a 408 stroker in my 99 Silverado. Btr stage 2 cam and ls3 heads long tube headers. When I first got the truck going it ran fine. After a couple weeks I changed the exhaust to a magnaflow and went on a 120 mile road trip towing a truck frame. No problems. The next day I went to drive the truck and under heavy acceleration (only under load) the truck sputters and sounds like it backfires through the exhaust. I can rev the engine in park or nuetral and it's fine. It misfires when it does this as well. Where should I start. It's a fresh built engine so I wouldn't think it's mechanical. Plugs? Tune? Wires? Any help or previous experience appreciated.
#7
On The Tree
iTrader: (4)
I had something like this happen to my 03 Yukon the o2's were reading crazy, crazy maF codes, sputtering, fine one day and crap the next. Changed plugs, wires, o2's, cleaned maF even swapped maF and still had the rich codes. Said screw it and changed the fuel pressure regulator and it was good as new. I had very good fuel pressure readings and would start up each time just ran like crap. Fuel pressure reg for he win on my part so that might be worth a check?
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#8
I had something like this happen to my 03 Yukon the o2's were reading crazy, crazy maF codes, sputtering, fine one day and crap the next. Changed plugs, wires, o2's, cleaned maF even swapped maF and still had the rich codes. Said screw it and changed the fuel pressure regulator and it was good as new. I had very good fuel pressure readings and would start up each time just ran like crap. Fuel pressure reg for he win on my part so that might be worth a check?
https://youtu.be/zB_53EnkvI4
#9
Moderator
iTrader: (19)
i made a video of what it does on acceleration. Is this what it was like?
https://youtu.be/zB_53EnkvI4
https://youtu.be/zB_53EnkvI4
#10
I plan on it, my work is closed where I have all my tools. I was more or less asking if it could be tune related whereas I have no control over it. I do appreciate the suggestions tho. To be honest I was hoping something other than spark plugs would be suggested. With the headers on there it's near impossible to even get a socket on them. I'll need to loosen the headers and move them