i was getting a random miss fire so i replaced the spark plugs icm and the coils (from rockauto)…

1998pontiacfirebird

i was getting a random miss fire so i replaced the spark plugs icm and the coils (from rockauto) when i started the car the idle would be stable for a minute the it would either go up or down for example 900rpm to 1300rpm or 900rpm to 600rpm after a while the engine would shut off it would start right back up do the same thing then shut off again after the 3rd time i put my code reader on it said crankshaft position sensor i called 2 of my friends one said replace it the other said it can not be the crankshaft position sensor if it was the car would not start he told me to change the throttle position sensor i can not throw a lot of money at changing out every sensor so i took the throttle body off cleaned it also cleaned the maf also cleaned the iac put it all back together still same problem but now when i put my code reader on it says no code over the past 2 weeks ive watched a ton of videos i saw one where a guy said if your icm gets to hot it would shut the engine off before i changed the icm and coils i watched a video and the guy said to use dielectric grease liberally to protect it from the heat from the engine and coils do i need to clean the dielectric grease off or do i need to replace sensors

thank you for your time

Comments (1)
No. 1-1
ScottyKilmer
ScottyKilmer

Editor

many things can cause misfires. from bad computer modules to worn valves to bad injectors to vacuum leaks, dozens of things. Rather than wildly guess, I'd advise finding a pro like me in your area to at least analyze it with his dealer level scanner