[ImperialCrown]

P1294-Target idle not reached. Probably too fast an idle speed due to a vacuum leak.
Check both ends of all the manifold vacuum hoses shown on your underhood vacuum map for one being accidently unplugged or disconnected or cracked.
A vacuum leak will cause excessive idle speed and set this code.
A leaking manifold gasket can also cause this, but if it happend just after a major service I would suspect a disconnected hose first.

 

[ImperialCrown]

A fairly common internal vacuum leak can occur underneath the intake manifold. It will draw air in from the crankcase.
An easy way to check for this is to remove the pcv valve and breather filter from the valve covers and block off the holes on a running engine. If you notice a vacuum developing at these holes after a moment, it usually means that the intake gasket underneath the manifold has failed.
There is a sheetmetal plate bolted to the underside. The manifold has to be removed to service this plate gasket.


Ram_Plenum06.jpg

 

[ImperialCrown]

Then your intake manifold gaskets seem OK. Whew.
You don't have to use flammables to check for vacuum leaks as a 'much safer and accurate' spray bottle of water will temporarily seal a leak or change the engine speed momentarily. You may even visibly see the water get sucked in. Flammable vapors can also be inhaled by the throttle body and give you a false leak reaction/indication.
Try the red areas again, but with water.
You may have a vacuum supply line going to the LDP (leak detection pump) if this vehicle is OBD II evaporative emission control to run the tests. I didn't see it on your vacuum diagram.
A scan tool that can watch the AIC (idle air control) motor action (target idle vs. actual idle or number of steps) can also help, especially if it can count the IAC steps (open or closed). P1294 is usually set when the IAC closes off the air bypass fully and the idle speed is still too high. A vacuum leak (which is what the IAC is) will raise idle speed. A sticking IAC can make an engine race or not provide closed throttle decel.

 

[ImperialCrown]

Unplugging the IAC will stop the plunger where it last sat and turn on the 'ck eng' light.
Disconnecting the battery should reset the adaptive 'learned' minimum idle value if you want to try that. It should take a few moments to settle down and relearn.
By cycling the key off/on, you should see the IAC plunger move out and in.
I still suspect a vacuum leak.

 

[ImperialCrown]

Hydrocarbon fumes from fuel may deteriorate and dissolve many RTV's. It isn't good practice to use it in fuel system components. A properly fitting o-ring would be the way to go here.

 

[ImperialCrown]

I believe that P1294 is only set when the IAC has already backed off the idle as much as it possibly can (0 steps) and still can't attain the proper 'target' idle speed.
The PCM watches the IAC steps as well as engine idle speed in order to compensate for changes in engine speed and load. I doubt that worn or misfiring spark plugs can fool the PCM into setting P1294. The PCM is pretty accurate in communicating the problem it is seeing.
A throttle that isn't closed or is misadjusted is treated as a vacuum leak. There is no idle speed adjustment screw as the PCM controls that watching the RPM and adjusting the IAC.
The screw that is there on the throttle body is a minimum air adjustment and if tampered with could cause this code. Could someone have messed with it in the past to try and cure a stalling issue/rough idle, etc?
A scan tool display to see what the PCM is seeing might help diagnosis here.


P1294-TARGET IDLE NOT REACHED

When Monitored: With the engine idling and in drive, if automatic. There must not be a
MAP sensor trouble code or a throttle position sensor trouble code.

Set Condition: Engine idle is not within 200 rpm above or 100 rpm below target idle for
14 seconds. Three separate failures are required to set a bad trip. Two bad trips are
required to set the code.

POSSIBLE CAUSES:

THROTTLE BODY
THROTTLE PLATE/LINKAGE BINDING
VACUUM LEAK
THROTTLE BODY DIRTY

 

[ImperialCrown]

An OEM IAC would be what I would recommend to start with. Could that be the whole problem?
See if the parts store will take the old one back.