Hi guys,

I have a 84 TA with a built 305, and it normally runs smooth, and as fast as i want to go!

On my way home tonight it developed a miss just one here and there, but by the time i got home it was Almost constant. it is definently a miss.

my question is what could cause it to miss? wires are good, plugs are newer, and cap and rotor are in good shape.

what is weird is that it had no rhyme or timing to go with it. it missed at random times and different severity also

my thought is the ignition control modual, but i have never had one act like this, all the other ICM's that have gone out just flat out quit working with no spark at the spark plugs.

Also every time it missed the tach would jump around quiet a bit, but only when it was misfiring

any thoughts experiences would be great

Thanks guys

 

Bad batch of gas maybe?

 

Im researching this problem has well,I got a ghost miss an jumping tach cant figure it out,only happins at low rpm ,when rpms are constent,give it a little gas and it goes away.

 

I had a jumpy tach, and variable miss as well. Replaced distributor...all is well. Not sure but I think the gear gets some flank wear at the pitch diameter which causes it to put a slap on the pin. Whatever it was, it was all fixed with a new distributor.

 

something similar happened to me a year ago, i just got done rebuilding my whole camaro, rebuilt engine and everything, i start it up and it misses, so i mess with it here and there and nothing helped at all, i thought it might be the distributer one day so i go out there determined to fix it, i start it up, and no miss, ever again, drove the car for a long time and it never missed again, my guess was my distributer was weird so try to change that, i guess i must have just gotten lucky?

 

YES SIR,you are correct,replaced dist and Varoom no misses and idles better,drives better,even sounds better.

 

LOL,well it was fine for a day...then right before I got home cruzzing down my street at like 1100-1200 rpm i see a slight jump on the tach and feel a slight hesitation...eeerr wtf???

 

Is it an after market distributor or refurbished? The after market ICM's are known to cause a jumpy tach, if you replace it with a gm ICM it might fix your problem, but at the least would fix a jumpy tach.