engine stumble just above idle then loud exhaust backfire

[Galtmn]

Idle sounds normal in park...at anything other than slight throttle pressure it starts to break up...if depressing throttle very easy it does ok up to about 2k to 2500 rpm then starts breaking up consistanly. If throttle is pressed normally like just to rev it up a bit it misses and back fires very loudly through exhaust and exhaust smoke is noted.
I replaced the fuel pump due to original was only showing about 30 psi at idle. New one Walbro is running at 40psi idle...didn't help. I replaced the plugs, plug wire set AC Delco and Coil Pack AC Delco...didn't help.
I'm thinking a new Ignition module??? Reading some previous post's it sound like a reasonable posibility.
This all started out of the blue while driving and all was good, then took off from stop light and there it goes.
thanks!

 

[kidglok]

a faulty ignition module can cause some crazy things. Ive had a brand new one that would work fine under normal driving but as soon as i got into boost it would do what your describing. If you can, try swapping with a known good one before you go out and spend $200 on one. Another possibility is the cam sensor.

what chip is in the car?

 

[Stevehardin87gn]

X2...........control module....get an AC Delco.

 

[Stevehardin87gn]

ooo make sure and check the cam sensor is adjusted properly........would do that b 4 I put a control module on. good luck!

 

[J-B Racing]

Pretty sure it's the Cam Sensor. Do a quick test. Start the engine and unplug the the Cam Sensor. That will put the car in MPFI. Go for a spin and push boost. If it does not do it. You know the Sensor or a Wire may be cut near the Sensor. Stop the Car. Unplug the ECM Wire to reset the Computer otherwise your Engine Soon light will never go off.
Easy test that costs nothing.

Good Luck

 

[TurboBuRick]

Sounds like the tab broke off the cam sensor wheel.

RL

 

[CGASTON]

Idle sounds normal in park...at anything other than slight throttle pressure it starts to break up...if depressing throttle very easy it does ok up to about 2k to 2500 rpm then starts breaking up consistanly. If throttle is pressed normally like just to rev it up a bit it misses and back fires very loudly through exhaust and exhaust smoke is noted.
I replaced the fuel pump due to original was only showing about 30 psi at idle. New one Walbro is running at 40psi idle...didn't help. I replaced the plugs, plug wire set AC Delco and Coil Pack AC Delco...didn't help.
I'm thinking a new Ignition module??? Reading some previous post's it sound like a reasonable posibility.
This all started out of the blue while driving and all was good, then took off from stop light and there it goes.
thanks!

Do you have a scanmaster? What are the readings when it does it? Have you tried swapping MAF (If I remove/unplug my GEN II, my car stumbles and pops)? Are you 100% certain that your plug wires are not CROSSED? I would buy the TR6 before I go buying a $200 ignition module. Have you had your intake or timing cover of recently?

 

[Jerryl]

Idle sounds normal in park...at anything other than slight throttle pressure it starts to break up...if depressing throttle very easy it does ok up to about 2k to 2500 rpm then starts breaking up consistanly. If throttle is pressed normally like just to rev it up a bit it misses and back fires very loudly through exhaust and exhaust smoke is noted.
I replaced the fuel pump due to original was only showing about 30 psi at idle. New one Walbro is running at 40psi idle...didn't help. I replaced the plugs, plug wire set AC Delco and Coil Pack AC Delco...didn't help.
I'm thinking a new Ignition module??? Reading some previous post's it sound like a reasonable posibility.
This all started out of the blue while driving and all was good, then took off from stop light and there it goes.
thanks!

I had a very similar issue. . . .
The car would exactly what yours is doing. . . . which was resolved . . . and now re-appeared.

Unplugging the cam sensor did not resolve it on this car.
Installed PL . . . . noticed the NB O2's would drop, which to me . . . indicated a lean/misfire. . . . when combined with wet plugs.
Swapped coil, no change . . . swapped ignition module to my emergency/back-up Series 2 system , and problem solved . . . No more exhaust popping.
FWIW . . . The module was not "sticky" at all . . . . and was OEM.

Guess the point being . . . it’s more than likely ignition related since nothing else was changed.
I will be keeping an eye on this to exorcise the demon . . . . . .

 

[Galtmn]

Thanks for all the comments...It is now corrected and some of you hit it right on the head...CAM SHAFT SENSOR!!! Runs like a top again.THANKS!!!

 

[Galtmn]

Sounds like the tab broke off the cam sensor wheel.

RL

That was it exactly! thanks!

 

[Galtmn]

Pretty sure it's the Cam Sensor. Do a quick test. Start the engine and unplug the the Cam Sensor. That will put the car in MPFI. Go for a spin and push boost. If it does not do it. You know the Sensor or a Wire may be cut near the Sensor. Stop the Car. Unplug the ECM Wire to reset the Computer otherwise your Engine Soon light will never go off.
Easy test that costs nothing.

Good Luck

That was it! Thanks!