I just picked up a 89 gta(71,000 miles),and it seems to run excellent except for the fact you can feel a miss when In gear,at idle up to about 1500 rpm,then fades away.Its very faint,but its ther,you can feel it most when on the brake,any ideas before I get a diagnostic done?

 

if ur not throwing a code then dont bother with the diagnostics bc the computer cant read it... if it did then the code would show... could be a couple of things, i would check ur plugs/wires/cap... sumtimes the coils and control modules do weird things.i would also check ur timing. if that all checks out ok then i would disconect the knock sensor and take it for a quick run to see if it stops or disconnect the ecm spark advance connector and see if it runs better.

other things to check would be TPS voltage, IAC etc

just a stupid question are u sure its a miss and not engine noise/rattle/resonace etc bc that seems to only happen at idle and low rpms

 

yea,no codes.I decided to pull a plug,#8 the hardest to get to,it looks very old and the plug wires look old too,# 8 wire pulled apart when I tryed to remove it.So hopefully this is all my troubles right here. Ill replace the plugs and wires later this week and let yeah know,THX

 

Did your car run better after plugs and wires?

 

Yeah,a little bit,those plugs were nasty black,but Ive also discovered my fuel pressure at idle is 10 pounds to low ,the miss seems to dissapear under acceleration,until you hold the rpms study then she shakes,but not much,Im guessing this is cause my fuel pressure is low.Its in storage for the winter,so I wont have a solution to post till spring....winter sucks