Missfire intermitent problem (video)

[gn_steve]

Hi everybody i am having a big problem with my car its missfiring but not all the time but when ut dies its bad and sometimes when it missfires i let go of the gas press it again and its ok???

I will post another video of under the hood shortly


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[mikestertwo]

Your O2's are showing lean and I see a error code 34 Mass Air Flow.

 

[mikestertwo]

Check your grounds on the back of the head.

 

[gn_steve]

Your O2's are showing lean and I see a error code 34 Mass Air Flow.

Yes code 34 cause i unpluged the maf to see if that was the problem just did not erase the code! And how can it be lean on idle???


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[gn_steve]

Check your grounds on the back of the head.

There not on the back of the head but on a stud on the back of the intake plus from that stud there a ground going to the negative battery cable on the fender!


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[Speed_Dreamin']

I'm going through the same thing right now. You rattled off many things in your video that you replaced, but I didn't hear you say ignition module. Is it new? I've also heard that even a new ignition module can be bad, which makes things even more frustrating...

So far I have replaced the MAF, O2 sensor, plugs and ignition module. Checked compression and the coil. Plug wires are next. Sounds like you are ahead of me.

Good luck.

 

[626gn]

Different approach... what specific brands of new parts were put into the car? Just because a part is new doesn't mean it's right for our cars.

 

[Daniel PErkins]

Steve--I have watched your video twice and have a couple of questions--what type of maf are you running? Stock or ls1 or lt1? 2. What chip are you running? 3. You say new motor--misfires are either fuel or spark related. Start with spark--wires, plugs, crank sensor, ignition module. Can you swap known good components off a buddies car to do a process of elimination? If it was a cam sensor problem the car would not start up. What is your fuel pressure at idle? Double check the ground integrity--how much resistance is in your ground circuit? Ok--try to answer all these and let us know your findings. Dp

 

[gn_steve]

Steve--I have watched your video twice and have a couple of questions--what type of maf are you running? Stock or ls1 or lt1? 2. What chip are you running? 3. You say new motor--misfires are either fuel or spark related. Start with spark--wires, plugs, crank sensor, ignition module. Can you swap known good components off a buddies car to do a process of elimination? If it was a cam sensor problem the car would not start up. What is your fuel pressure at idle? Double check the ground integrity--how much resistance is in your ground circuit? Ok--try to answer all these and let us know your findings. Dp

Running stock maf a turbo tweak chip for 60's a racetronix fuel injector harness 60 pound edge product injectors coil is good but did not replace ignition module fuel pressure is at 43psi line off crank sensor was changed for the new type plugs are brand new autolites 103's spark plug wires are brand new taylor 8mm wires
Unpluged cam sensor and whent for a ride same thing!


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[mikestertwo]

Is your TT chip open or closed loop idle? If it is an open loop idle your O2's a way low. It's not a good idea to run a ground from the computer grounds on the engine to the ground on the fender. Those are signal grounds for your sensors and those have to go back to the computer and no where else. Ground currents from other devices on the car can effect sensor readings that the computer uses to make adjustments. It can cause a shift in O2 readings for one.

 

[gn_steve]

Problem solved defective ignition module thanks guys for your help and input!


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