backfiring under hard acceleration??
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Senior User
Joined: Aug 2003
Posts: 346
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From: Minnesota
backfiring under hard acceleration??
i got a friend that has a 94 150 with 302 auto and he is noticin like a backfire when he stomps on the gas. im thinkin timing is off but i cant see how that could happen and it should always be runnin like crap, not just on hard accel. what else could cause this? maybe bad spark plugs? Thanks
Post Fiend
Joined: Mar 2002
Posts: 19,402
Likes: 38
From: Bonita Springs FL
A tuneup is rarely a bad idea, but the first thing I would do, especially when you're talking backfire, is check the timing. It doesn't really matter how it got screwed up - maybe a previous owner messed with it, maybe the hold-down bolt loosened up, maybe the timing belt skipped a tooth.
Make sure you disconnect the SPOUT connector near the distributor and set the timing to 10 BTDC.
Make sure you disconnect the SPOUT connector near the distributor and set the timing to 10 BTDC.
Post Fiend
Joined: Mar 2002
Posts: 19,402
Likes: 38
From: Bonita Springs FL
Not necessarily. Timing can be off as much as 10 and you won't notice it at idle. I don't know if you can rent a timing light at a store or not. I have my own, so I never tried to rent one. 
I think I paid about $40 for mine at Sears.
I think I paid about $40 for mine at Sears.
Senior User
Joined: Apr 2004
Posts: 352
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From: Millbrook, AL
My 96 was doing the same thing when I was hard on the acclerator and it was changing gears. I just did a full tune up on it, plugs, wires dist cap and rotor and this cured it. I was using bosch platinums and I still think they were responible. I went back with autolite platinums and haven't had any such problem since, even with the same amount of miles on the plugs. I read somewhere the bosches were designed for aluminum heads and they don't ground well on cast iron.
