New and need help PLEASE

[Thatguywins1]

2001 Chevy Tahoe 5.3 2wd LS on initial start, the truck goes to 3800 RPMs and bounces up and down for about 30 seconds, and then it dies. I have already cleaned the throttle body Even changed the intake gaskets Please somebody help me if you know what’s going on or have seen the similar situation. Every start it goes immediately to 3800 RPMs.

 

[Miami-Dade]

@Thatguywins1 Moved you here for your issues.
Welcome from Miami&NYC!

 

[Thatguywins1]

Thanks for the welcomes but I really really really really need somebody to help me figure out this crap with my car. I’m so tired of being stranded.

 

[Fless]

Welcome to TYF from windy Colorado! (Feels like Wyoming today...)

I would say to get a scanner on it that can read live data, and someone who can look at the data to see if something is not right.

How about a little more history? How long have you had it, miles on the truck, regular maintenance been done?

Also how long has this been going on and was any work done prior to the problem?

 

[OR VietVet]

Welcome to the forum from Oregon.

@Miami-Dade moved you here for a better chance at responses to your problem.

Any CEL's? You may be able to help the problem by cleaning the MAF. May even have to replace the MAF. Any recent work before the problem happened? May have a Throttle Position Sensor problem as well. The one I listed is without traction control.

More Information for GM GENUINE 19330121

More Information for ACDELCO 2134668

 

[Thatguywins1]

Welcome to TYF from windy Colorado! (Feels like Wyoming today...)

I would say to get a scanner on it that can read live data, and someone who can look at the data to see if something is not right.

How about a little more history? How long have you had it, miles on the truck, regular maintenance been done?

Also how long has this been going on and was any work done prior to the problem?

I have had the truck for five years I changed the oil every 5000 miles currently 384,000 miles This problem occurs following a motor swap, which was swapped out with eighth digit vin T. I did all the work myself I can’t find a vacuum leak anywhere.

 

[Thatguywins1]

Welcome to the forum from Oregon.

@Miami-Dade moved you here for a better chance at responses to your problem.

Any CEL's? You may be able to help the problem by cleaning the MAF. May even have to replace the MAF. Any recent work before the problem happened? May have a Throttle Position Sensor problem as well. The one I listed is without traction control.

More Information for GM GENUINE 19330121

More Information for ACDELCO 2134668

You know that’s the crazy thing is there is no CELS at all NONE PREVIOUS NONE STORED and I have traction control

 

[Thatguywins1]

 

[OR VietVet]

There is a listing for traction control TPS at RA. There is also known problems with the wiring harness to the TPS. The engine swap include using the old TPS?

 

[Fless]

So, if I understand correctly, you replaced your LM7 with another LM7. True? And the new engine is from what year?

Did you use your original throttle body and throttle cables, or do some kind of a modification? What parts from the old engine were put on the replacement?

 

[Thatguywins1]

There is a listing for traction control TPS at RA. There is also known problems with the wiring harness to the TPS. The engine swap include using the old TPS?

Yes only because the donor motor had a cable throttle body

 

[Thatguywins1]

So, if I understand correctly, you replaced your LM7 with another LM7. True? And the new engine is from what year?

Did you use your original throttle body and throttle cables, or do some kind of a modification?

The engine came out of a 2001 Chevy Silverado. Yes it was an LM seven with 160,000 miles on the engine. I did use my throttlebody because mine is drive-by pedal. No modifications were done. I can show you the difference in throttle bodies

 

[Thatguywins1]

 

[Thatguywins1]

the one that came stock on my truck is different uploading photo now

 

[Fless]

What parts from the old engine were put on the replacement?

Or, if too many, what parts on the new block were retained?

 

[Fless]

No need to show us the diff between throttle bodies. You would need to use your cabled one, we get that.

 

[Thatguywins1]

 

[Thatguywins1]

What parts from the old engine were put on the replacement?

Or, if too many, what parts on the new block were retained?

I put brand new knock sensors with harness valve covers with gaskets plugs and wires brand new only thing that came over to this engine was the throttle body

 

[Thatguywins1]

OK so as soon as the engine is started, the engine immediately goes to like 3800 RPMs and balances back-and-forth from 3800-3700-3800 for 10 to 15 seconds, and then the RPMs drop way way low to the point to where it struggles to stay running for 5 to 10 more seconds until it dies

 

[Fless]

Well, I'd recommend looking at some live data. Just a guess, but you may have a MAF that's over-reporting, or a coolant temp sensor that's dead or mis-reporting. Those aftermarket intakes can cause issues, too, with unreported air (as in a disconnected or unsealed vacuum hose).