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Discussion Starter · #1 ·
So on recommendation for a hesitation issue this truck had earlier at 1500 rpm I changed the spark plugs in the truck and that got rid of our hesitation issue.

Before we did the plugs the idle was at 800-900 RPM.

It had OEM Champions in it and I replaced them with OEM Champions mind you there was nothing left of the electrodes and the gaps were pushing .070 or higher. (guy told my father that it had lifetime plugs in it) So there was at least over 100+K on these plugs.

*NO CODES

The truck has a high enough idle in drive that it accelerates on its own to over 60 km/h slowly but, when you hit the gas and go to say 90 km/h it takes forever to drop back down to 60-70 km/h but it won't go any slower. (This is all with the foot far away from the throttle.)

Should I just adjust the Grub screw on the Throttle Body to drop the Idle down or what else could possibly be the issue? I check the TB and the throttle is closing as far as the grub screw allows it, probably around 1/8" of the grub screw sticking out.

I did not touch anything else, would a vacuum leak cause an Idle this high?

Or would a stuck TPS sensor cause the issue?

What is the resistance value for a new TPS sensor?

Would unplugging the battery clear the ECU and change the timing or TPS position? I did not unplug the battery when I changed the plugs.

Any help is appreciated!
 

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Check for a vacuum leak. Most of the time, when I've diagnosed a high idle, it's because of a vacuum leak. Try doing the old hose-in-the-ear trick to find it (put a small hose in your ear and poke around until you hear a hiss from a vacuum leak) or just pull the vacuum hoses and visually inspect. Check vacuum lines and also the intake-to-head mating surfaces and throttle body gasket for a bad seal.
 

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Discussion Starter · #3 ·
Cleaned the TB and IAC made sure we had full Voltage at iac sensor harness.

Checked the resistance on the TPS .005 closed and goes from .005 to.001 at WOT.

Checked for vac leaks and have none.

Only thing I can think is the iac is not adjusting for idle speed.

You cannot adjust the idle grub screw as it uses a torx centre pin screw so that rules that out.

Got these 3 codes but that's just cause I removed the clips to all 3 parts when the engine was running. Disconnected the battery for over an hour too.

Any other ideas. Would a bad coil boot cause a high idle? I wouldn't think so myself.

Cannot explain why we get this issue after just changing spark plugs.
 

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it's possible that the idle air controller is stuck partially open. Grab a couple of them from the junk yard and try them on your engine. Also, did you check your brake booster line for leaks?
 

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Did you figure out what the issue was?

Did you figure out what was causing this issue? I have the exact same problem with my ram at the moment.
 

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Have you fixed them problem? I have a 03 4.7 that hesitates once after being parked for 20 or more minutes and about 1500rpm I get a hesitation as if out of gas or too much gas some time a jerk. I'll let the gas go and idol for 5-10 seconds then runs fine.

I have changed:
TPS
IAC
both 02 sensors
Crankshaft sensor
PCV
Air Temp Sensor
New battery
MAP sensor
Fuel relay
manually cleaned throttle

still have issue. please help.
 

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I realize you might no longer have this truck. With that being said if you do I would double check the rubber hose at the back of the intake. This hose runs from the back of the intake to the oil cap.
 
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