Engine loping while in gear with brake on, concerned!!!

[warriorwagner]

Looking for some help, last week I put the truck in reverse and it loped out of the driveway. Today, leaving the auto parts store waiting to pull into traffic, it loped again...in gear with the brake on. So twice now it's loped on me.

No check engine light on, once I accelerate, it ran fine. Maybe a sensor or something???

Any help would be greatly appreciated.

 

[JayRolla]

Looking for some help, last week I put the truck in reverse and it loped out of the driveway. Today, leaving the auto parts store waiting to pull into traffic, it loped again...in gear with the brake on. So twice now it's loped on me.

No check engine light on, once I accelerate, it ran fine. Maybe a sensor or something???

Any help would be greatly appreciated.

Take them big cams out?

Does it have a misfire at idle at all?

 

[warriorwagner]

Take them big cams out?

Does it have a misfire at idle at all?

No misfire at idle, nice and smooth. The loping is intermittent also, which is the worst. One twice so far in two weeks of ownership.

Any ideas????

 

[JJH]

No misfire at idle, nice and smooth. The loping is intermittent also, which is the worst. One twice so far in two weeks of ownership.

Any ideas????

You might check/clean the MAF. My 2000 V6 would lope on start-up, after sitting for a while, at random. Eventually the MIL came on with a lean condition. Here's a decent post on cleaning the MAF.

 

[warriorwagner]

You might check/clean the MAF. My 2000 V6 would lope on start-up, after sitting for a while, at random. Eventually the MIL came on with a lean condition. Here's a decent post on cleaning the MAF.

Thanks, I'm going to clean it this afternoon and see if that does the trick.

 

[ukrunner]

Is your AC on?

 

[warriorwagner]

Is your AC on?

Yes, but it was loping quickly, not when the compressor was starting and stopping.

 

[JJH]

Yes, but it was loping quickly, not when the compressor was starting and stopping.

I noticed you asked a question about the PCV valve on another thread, and didn't want to thread jack that one. Here is a link to a write up on another forum.

 

[warriorwagner]

I noticed you asked a question about the PCV valve on another thread, and didn't want to thread jack that one. Here is a link to a write up on another forum.

Found it, thanks for the link.

Warrior

 

[gamefreakgc]

Does it only do it when you have the brake pressed? If yes, it could be an issue with the brake booster or the check valve in the brake booster vacuum line. Or a leak somewhere in the system.

Or if only when the engine is hot, could also be the Idle Air Control (IAC) valve that's under the throttle body. Would require taking off the throttle body and dissasembling the IAC to clean it out.

 

[warriorwagner]

Does it only do it when you have the brake pressed? If yes, it could be an issue with the brake booster or the check valve in the brake booster vacuum line. Or a leak somewhere in the system.

Or if only when the engine is hot, could also be the Idle Air Control (IAC) valve that's under the throttle body. Would require taking off the throttle body and dissasembling the IAC to clean it out.

It hasn't done it in a couple of days, but it "loped" when I was backing out of my driveway last week so it will "lope" in gear moving too. I'm going to clean the MAF tonight when I get home, just been to busy at work to deal with it.

Thanks and I'll let you know how the MAF looks when I take it out.