miss fire

[97cleantahoe]

bad miss fire HELP PLEASE

ok, when I put into reverse or drive I can here a slight backfire in the tail pipe and it seems to struggle when I give it any gas. I have changed spark plugs, wires and coil pack but, it still does this. it also has really bad gas mileage now, can anyone help.

 

[mygreen98]

service engine light on?

 

[96ProCompTahoe]

did you check the distributor cap and rotor?

 

[97cleantahoe]

yes the ses light is on and it flashes but has been hooked up to a reader and says no bad elec and I did check rotter and cap its fine. I just found it has low fuel press and I changed the filter did not help. could it the pump. please help only transportation.

 

[tahoeman21]

check your fuel regulator

 

[bowhunter22]

How many miles are on the motor. Kinda sounds like the distributor drive gear at the cam.

 

[YukonJenNV]

Could it be the intake gasket is leaking, I had that problem with mine. I had a rough idle, and it didn't seem to have much power as I wound it up. It would pop under acceceration. I pulled the intake off, and found where the gasket was leaking.

 

[mygreen98]

did u say it flashes the ses light? if its flashing while driving, that means bad misfire in the ignition system. post your findings

 

[97cleantahoe]

yes the ses light flashes. It has 170000, but has been well kept. I changed the fuel pump and it did not help. My brother thinks it is the Cadillac converter but I dont. I think maybe an EGR valve. I dont really know and nobody seems too. Im gonna look at the intake gasket but I dont think that would turn ses light on. If you have had this prop or know someone that has please help me. It is my only transportation and I am starting college real soon.

 

[tim@sp]

get it to someone with a snap-on scanner or one that has Misfire data on it. Find out if its random or if its on one cylinder...

My issue turned out to be the injector plug on the upper intake. I just pulled it off, used some contact cleaner and diolectric grease and the misfire went away!!

Tim

 

[olpir8]

Yep, I had the same thing. It turned out to be cyl #3 always misfiring.
I replaced the injector (cpi) and that fixed it.