88 chevy 454 backfire

I am at a loss with this one. I replaced the intake and exhaust gaskets in my 88 454. She was chugging and had visible and audible exhaust leaks. The engine runs great now at idle and timing is steady at 4 deg BTDC. New plugs, wires and distributor cap. Manifolds were torqued to specifications and to my knowledge I put everything back by the book. I now have a backfire through the TBI from 25 to 45 MPH usually under load. (9K suburban is a load at level). The backfire will stop and I get full power without hesitation if I floor it. I replaced the coil and have triple checked everything. I am getting ready to dump $95 on a distributor as the electronic advance looks funky to me. Anyone else have any other suggestions?

Reply to
curt.bussiere
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recheck your wire order. Also make sure your #1 is truely at #1 on the distributor and not 1 off all the way around.

just a suggestion. its gotten me a time or two

Reply to
ed

Pull the dist cap and give the rotor a side to side "wiggle".

Any slop is bad and pretty common on high mile distributors.

Is sloppy a rebuild or replacement is in order.

Reply to
anumber1

Reply to
slick

Those distributors can be turned far enough to make the wiring order look correct but still be off by 1 all the way around.

Ted

Reply to
Ted Mittelstaedt

Reply to
curt.bussiere

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