Vehicle:
2003 Envoy XL SLE
4.2L I-6
Mileage: 92,000
Hi everyone -
I am desperately looking for help on the rather serious REP issue.
Yesterday, for example, REP manifested itself no fewer than 45 times while my girlfriend was driving it. Today, I took the vehicle for my usual 34 mile commute and I got it once.
Symptoms: In the 10-20 seconds leading up to the truck going into REP mode, throttle response is sluggish and or "notchy" (meaning the truck accelerates not smoothly or linearly, but in a 'stepped' mode). Then, there is a moderate shudder lasting, at most, 2 seconds, then - boom into REP mode. Both Check Engine and REP lights come one.
Turning the truck off/on gets it out of REP mode. Check engine light stays on.
Environment: South Florida winter, little rain, low moisture. I was thinking we were looking at some sort of moisture issue with the wiring or harness, but in this rather dry enviroment I am not seeing it. Also, during rainshowers - the REP neither increases or descreases.
I've been dealing with this issue for a year now, if not more.
What Has Been Done:
I have replaced the Throttle Body Assembly (Delco). This did not alleviate the TEP issue.
I took the truck to the GMC dealer. They have no idea what was going on but noticed that fuse-box was out of a Trailblazer and not an Envoy. They said this could be a cause, but not 100% certain. That repair\labor cost me $1200 and did not resolve anything.
What I do have, but have not installed yet, is an accelerator, throttle-by-wire assembly. I got that after reading in some spots that this could be a culprit.
Codes:
After having the check engine light on for a while, I hook up the code reader to it and it comes back with these codes:
P0171
P0172
P0340
P1221
P1516
P1481
I cleared the check engine light and codes then took her out for a ride to try to induce another REP. Upon starting the motor, I get the following code:
P0340
HOWEVER, this code does not trigger the Check Engine or REP light.
About 15 minutes into my ride, the usual shudder and REP event occurs. This time the reader tells me:
Code 1: 1221
Code 2: 0340
Code 3: 1221
Odd that 1221 showed up twice.
Anyway, engine-codes.com tells me that GMC 1221 has to do with TPS 1-2 correlation. As mentioned before, this is a genuine Delco aftermarket throttle body\TAC.
I still have the old throttle body.
I will also note that the engine idles rather roughly. I thought it was an engine mount issue, but a mechanic friend of mine took a quick look at it and said it was OK there.
So, I am wits end here. I cannot discern a pattern and I need this vehicle to be working properly.
Any ideas would be *greatly* appreciated.
George
2003 Envoy XL SLE
4.2L I-6
Mileage: 92,000
Hi everyone -
I am desperately looking for help on the rather serious REP issue.
Yesterday, for example, REP manifested itself no fewer than 45 times while my girlfriend was driving it. Today, I took the vehicle for my usual 34 mile commute and I got it once.
Symptoms: In the 10-20 seconds leading up to the truck going into REP mode, throttle response is sluggish and or "notchy" (meaning the truck accelerates not smoothly or linearly, but in a 'stepped' mode). Then, there is a moderate shudder lasting, at most, 2 seconds, then - boom into REP mode. Both Check Engine and REP lights come one.
Turning the truck off/on gets it out of REP mode. Check engine light stays on.
Environment: South Florida winter, little rain, low moisture. I was thinking we were looking at some sort of moisture issue with the wiring or harness, but in this rather dry enviroment I am not seeing it. Also, during rainshowers - the REP neither increases or descreases.
I've been dealing with this issue for a year now, if not more.
What Has Been Done:
I have replaced the Throttle Body Assembly (Delco). This did not alleviate the TEP issue.
I took the truck to the GMC dealer. They have no idea what was going on but noticed that fuse-box was out of a Trailblazer and not an Envoy. They said this could be a cause, but not 100% certain. That repair\labor cost me $1200 and did not resolve anything.
What I do have, but have not installed yet, is an accelerator, throttle-by-wire assembly. I got that after reading in some spots that this could be a culprit.
Codes:
After having the check engine light on for a while, I hook up the code reader to it and it comes back with these codes:
P0171
P0172
P0340
P1221
P1516
P1481
I cleared the check engine light and codes then took her out for a ride to try to induce another REP. Upon starting the motor, I get the following code:
P0340
HOWEVER, this code does not trigger the Check Engine or REP light.
About 15 minutes into my ride, the usual shudder and REP event occurs. This time the reader tells me:
Code 1: 1221
Code 2: 0340
Code 3: 1221
Odd that 1221 showed up twice.
Anyway, engine-codes.com tells me that GMC 1221 has to do with TPS 1-2 correlation. As mentioned before, this is a genuine Delco aftermarket throttle body\TAC.
I still have the old throttle body.
I will also note that the engine idles rather roughly. I thought it was an engine mount issue, but a mechanic friend of mine took a quick look at it and said it was OK there.
So, I am wits end here. I cannot discern a pattern and I need this vehicle to be working properly.
Any ideas would be *greatly* appreciated.
George