Early 99 throttle problems

[LKR Racing]

I have a 99 that threw a code for the IDM and I replaced it but it is still having the same problem. The problem is that after running a while if I let of the throttle it turns the check engine light on and there is no throttle but if I put it in neutral it comes right back. I replaced the throttle position sensor and had a wiring diagnostics done to check for broken wires in harness. I am at a loss. The truck does have 276,000 miles on the original automatic tranny.

Thanks in advance

 

[JLDickmon]

that's a good one..
the throttle responds but the truck has no drive, or the throttle doesn't respond?

 

[LKR Racing]

Could it be a sensor in the tranny or the tranny needing rebuilt. Or could the cat be plugged and when it heats it cause to much back pressure and chokes it down?

 

[LKR Racing]

The throttle does not respond.

 

[Tail_Gunner]

Or could the cat be plugged and when it heats it cause to much back pressure and chokes it down?

Your early 99 still has a "kitty"?


on edit: I'm wondering if it might be a EBPV thing.
Maybe something to do with the EBPSensor tube going from the rt side exhaust manifold to the sensor near the top/front of the motor by the HPOP reservoir.

A way to check for it would be unplug the wire connector for the EBPV acuator on the turbo pedestal. If the problem goes away, you've got it narrowed down.

 

[LKR Racing]

They have emissions here and are getting ready to get rid of them.

 

[LKR Racing]

Thanks I will try that tomorrow.

 

[JLDickmon]

The throttle does not respond.

If that's the case, the first thing I think I'd do is get a seal pick or similar tool and squish the terminals on the connector for the throttle pedal sensor down a smidgen and try it again.

If the problem persists, do the "wiggle test" on the harness. It may have a wire broken inside the insulation causing an intermittent open. Remember, it only takes one strand of a braided wire making contact to pass a continuity test.