pls help me i have an 88 firebird came with a 2.8 now has an 89 5.7 performer rpm intake, holly 650cfm carb and an old 1 wire distribitor. The timing is set at 6 deg btdc, at idle it runs gr8 but when you put it in gear it jumps hard then under load it sounds like it has pre-detonation and no power above 3000 rpm. Ive changed the plugs gapped at 45, new wires,cap rotor and am getting a new coil. was told by a friend it was the chain or cam(stock)pls let me know what you all think thx

 

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Don't think it's the chain..when chains stretch, valve timing is retarded. which should help with detonation. Easys, enough to check though, bring #1 to TCD and put the HB mark on "0"..rotate the crank either way, noting the amount of degrees needed to move the rotor in the distributor. Post result should be less than a few degrees play.

 

sounds like a burnt plug or wire to me, that or a coil , or ignition module. tps might be shot., engine thinking your throttle isnt advancing and messing up the air fuel ratio