I'm trying to diagnose a problem with truck and can't pin point the problem. If I put the truck in drive and let off the brake it will slowly climb to 40mph. I checked the tension on the throttle cable and also looked for vacuum leaks and everything seems to be good. There is a delay in the motor going to it's idle rpm(around 800). When I shift from drive to park the rpms jump up to 1300 or so for a about 3 to 4 seconds then finally drops down to its 800rpm idle. This problem is affecting my braking as well due to the motor still wanting to push forward when I'm trying to brake. I was told by a fella I work with to pull off the sensor on the throttle body and clean it so I guess I'll give that a shot along with any other ideas y'all may have.

 

is this a new problem, or something that has been happening for a while? throttle cracker and follower tables could cause this.

 

What year PCM and harness are you running? What type of throttle body? Does it have a IAC? Do you have tuning software? Ya I know, allot of questions.

 

it's pretty recent..and if it was the throttle cracker and follower tables I would have to get with my tuner on this issue?

 

yes, you will need a tuner to make changes to the cracker/follower. if it is a new development, i would think that it is something else causing the issue. with a cool engine, start it, and spray carb cleaner or starter fluid around your gaskets. manifold gaskets, throttle body gasket, brake booster line, MAP sensor....listen for changes in the sound of your motor. if you hit a leak, it will rev up some. if you dont find a leak, clean your throttle body, MAF and IAC...if that doesnt work, take it to your tuner for a small adjustment. that's the steps i would take anyways

 

Pretty sure PCM is an 01 but I'll have to check with my tuner to be 100%. Throttle body is an 01 off of a LS6 intake(came off an 01 camaro). Not sure about the IAC, I'll have to get with the tuner. I don't have the software(yet).

 

Will do, thanks for the suggestions

 

Will be taking off the FAST 78 today to replace the seals. Almost positive this is wear the problem is coming from. Looking to do a little at home port job as well while it's off. Tony Mamo look out! lol

 

My sonoma did the same thing shortly after the LS swap was finished and I found it was the damm brake booster. But it was not making one single hiss when you step on the brakes and that is usually what is indicative of a booster failure.