It is not that we dont know or care for this issue, this is the F'in elec throttle - POS! - got that out of my system-
First- Any other codes? anything recient - repairs - replace- modifications?
Inspect the throttle body for the following conditions:
Start with a can of TB cleaner and check-
A throttle blade that is NOT in the rest position
A throttle valve that is binding open or closed
A throttle blade that is free to move open or closed WITHOUT spring pressure
If a condition is found, replace the throttle body assembly.
Then the problem working this starts with "connect Tech II", You will need a good scanner, DVOM wiring diagram
I read that P1516 to be something related to a dual-runner intake manifold system, but my opinion is effectively the same as kev2. More complexity and problems than it is worth. Regardless of whether it is the electronic throttle or something in the intake, it will take a serious scan-tool, and maybe more, to diagnose. It could be something cheap and simple, but I doubt it. If you aren't prepared for a steep-and-long "learning curve", I would recommend taking it to an expert who can work "hands-and-eyes-on". That's not to say we won't try to help you here, but it might not be a quick and easy journey.
First, Thanks for the input. . . We did change the A. I. R. ck. valve recently, and there are no other codes. I did clean the throttle plate and bore and it seemed to move freely but it was under spring pressure. As for the plate being in the rest position I'm not sure but I think it dosn't close tight when the key is off but when it's working I can hear the motor run when the key is turned to the run position and I assumed it was closing when this happened but I guess I should Know better than that. I have hooked a genisys scanner to it but I'm not knowledgeable enough with it to understand everything it may be telling me. This thing seems to act up when it sits for awhile, if you cycle the key enough times it will start to work, I did notice the other day that when I had the key on and the ck. engine light was on and it displayed reduced engine power that when I went and cleared the code and I happened to have my foot on the pedal as soon as the code cleared the throttle started to work fine again. I haven't had a chance to look at it again but I have to believe it will act up again. Thanks again
About the only thing you can do, it thoroughly clean the edges of the plate and bore of the throttle body......then, with key out of the ignition, remove the neg and then pos cables, and then hold them together for one minute.....this resets all modules in the vehicle......reconnect......clear codes, and then see what happens....
If it comes back, could be the throttle body unit, wiring problem, connection problem, PCM/ECM problem, etc.