I have a 92 rs with the 305 tbi and 5 speed. the car idles just fine, but when you start driving it, the tach starts jumping all over the place and it backfires and spits and sputters. Then it goes away, and all of a sudden it will do it again. I notice it more at slower speeds, but a little at higher rpms. I can't go WOT as it will fall on it's face and die. I have changed the TPS, and ignition module, and nothing changed, actually it got worse after I changed the ignition module. Any thoughts?

Bad coil or pickup both can go if the control module is bad .

hey i just got a 1986 camaro with a 92 v8 5.7 liter engine in it . the car was running really crappy so i had to change firing order on the car it was running alot better.. but still wasnt right about a week later i discovred the smog silinoid was disconnected from the terminal where it goes into the top of the engine also the electric was not pluged into the conponent. i did some research and found out the correct way to hook it up .. i started and drove the car about 5 blocks car seamed to be running better then ever smooth and more power . after i turned the car off and tryed to start it up the next day .. car does not start .. as u hold the exnition and pump the gas the engine gets slowly to full running speed as if its running and when i let go of the exnition it turnes off as quick as i let go ?? i also tryed removing the smog silinoid back to how i org found it still same story any suggestions ?? thanks

Check your timeing and your fireing order again and do you have any codes or check engine light ?

i do not have any codes showing when i first got the car the org firing order was making engine check light come on . hasent bin on since i changed it and timing and order is correct to ?

Whatever gives the RPM signal to the tach (like a cam sensor?) probably would also give the RPM signal to the engine computer and this would change the timing!

One of the inputs the computer uses to adjust the timing is RPM! This would probably be located in the distributor.

Also I suppose the wire from this sensor would go to your tach, and it is possible that if there was an intermittent short on this wire, it could mess up the RPM signal to the computer???

So might want to check your wiring before replacing that sensor. (To the tach and to the computer.)

Have you checked to see if you have fuel and spark ?

have you checked the reluctor. they will some time crack and this is where the EMC get it's signal from. if the reluctor wheel is cracked then it will only get worst as the rpm rise. this will also make the tach go crazy and make the car backfire as it doesn't know when to fire. just one thing to look at.

Or ignition module or pickup coil can do this also .