POP while accelerating now limp home

[MRaymond1]

Reposting from TrailVoy:

While accelerating from a stop (not racing) I got a POP from under the hood (maybe a backfire). Now the CHECK ENGINE light and STABILITRAC light are ON and I'm stuck in a LIMP HOME mode. The engine will not rev and I can't get above 10 MPH. The engine seems to be running OK but it idles rough. I can't get the codes checked since I can't drive it anywhere.

Scanning the other posts I'm thinking something might have happened to the throttle body. Any ideas on where I can start my search? Is there a way I can reset the computer to see if it was a one time deal?

Update since original post:
After sitting for 20 mins to poke around under the hood I found nothing. I restarted the engine yesterday. Check Engine was off and everything ran great. I drove around the block with no problems. Drove to the Autozone to check the codes; ALL CLEAR. Damn. Any ideas?

 

[CaptainXL]

Reposting from TrailVoy:

While accelerating from a stop (not racing) I got a POP from under the hood (maybe a backfire). Now the CHECK ENGINE light and STABILITRAC light are ON and I'm stuck in a LIMP HOME mode. The engine will not rev and I can't get above 10 MPH. The engine seems to be running OK but it idles rough. I can't get the codes checked since I can't drive it anywhere.

Scanning the other posts I'm thinking something might have happened to the throttle body. Any ideas on where I can start my search? Is there a way I can reset the computer to see if it was a one time deal?

Update since original post:
After sitting for 20 mins to poke around under the hood I found nothing. I restarted the engine yesterday. Check Engine was off and everything ran great. I drove around the block with no problems. Drove to the Autozone to check the codes; ALL CLEAR. Damn. Any ideas?

Has anyone been under the hood lately to work on anything?

 

[The_Roadie]

You probably had the REP light on as well. Reduced Engine Power. That happens if the PCM is displeased with the performance of the throttle body position sensors or the accel pedal sensors. A backfire could have blown the butterfly valve to an uncommanded position and upset the system. And now it's better, except for the risk of another backfire.

How many miles, and are you up to date on all fluids, spark plugs, and perhaps the upstream O2 sensor?

 

[MRaymond1]

The engine has 120,000 on the odometer. Fluids and filters are up to date but it probably needs spark plugs (I've never changed them). After reading about everyones problems with the throttle body I figured the backfire probably ticked the sensors off.
I changed the air filter as a precaution but it was ready to be changed..

 

[Ace1875]

The engine has 120,000 on the odometer.... probably needs spark plugs (I've never changed them).......

Spark plugs are rated to 100,000 miles max. use only AC Delco plugs

 

[fadyasha]

Wooooh never changed them... Those need to be changed for sure. At a point of time had a weak coil pack, at times would work and at times wouldn't. When out would limp and rough idle.

Same happened when one spark plug failed me, had a misfire on cylinder 1 and SES light blinking at me.

 

[khill]

Spark plugs are rated to 100,000 miles max. use only AC Delco plugs

 

[MRaymond1]

I'll pick up some ACD plugs and see if anything changes. No problems thus far but you know how these things go

 

[khill]

I'll pick up some ACD plugs and see if anything changes. No problems thus far but you know how these things go

http://www.acdelco.com/pdf/18-TP_H443020_SparkPlug.pdf

 

[gmcman]

MRaymond, do you have acess to a vacuum gauge? If so, check the needle of the gauge while the engine is idling and let us know if it's rock-steady, or fluctuating slightly. Because you may have experienced a backfire, this is generally because the intake valve may be hanging open and this could be from carbon deposits.

Just something we can eliminate from the equation.

 

[Mypetropig]

As I have learned from trying to research my problem, it could be a bad CPAS. If it fails to advance cam timing while accelerating it could lead to a back fire.

 

[CaptainXL]

As I have learned from trying to research my problem, it could be a bad CPAS. If it fails to advance cam timing while accelerating it could lead to a back fire.

Yeah unplug it and it will backfire. Scarred the crap outta me when I did it.

 

[fadyasha]

Yeah unplug it and it will backfire. Scarred the crap outta me when I did it.