02 Dakota 4.7 RPM Issues
#1
02 Dakota 4.7 RPM Issues
Amateur mechanic here...
I have an 02 Dakota 4.7 90,000 miles on truck and 65,000 on the motor.
It started with a surging rpm issue from stalling to 1100 rpm's.
I replaced the TPS sensor and 1 O2 sensor (pcm read voltage issues with both) and it seemed the level out but it is now idling high 900-1200 rpms. However this is not all the time.. about 75% of the time it sticks at these rpms.
I calibrated the TPS as such:
Disconnect negative terminal
Turn and hold key for 20s
Remove key
Connect battery
Put key in on position
Slowly press and depress pedal
Start truck
Same story
I replaced my IAC valve and didn't seem to help much. But If you adjust the IAC you obviously get different rpms because it's open further or closed further. Why this is adjustable is beyond me. That may be an issue.
What is really getting to me though is if I tap the top of the throttle body lightly with a wrench, the rpms all a sudden drop to 600, every time! I cannot figure how this is happening.
I do have a multimeter and any suggestions of what anything should be I can test them.
Thank you
I have an 02 Dakota 4.7 90,000 miles on truck and 65,000 on the motor.
It started with a surging rpm issue from stalling to 1100 rpm's.
I replaced the TPS sensor and 1 O2 sensor (pcm read voltage issues with both) and it seemed the level out but it is now idling high 900-1200 rpms. However this is not all the time.. about 75% of the time it sticks at these rpms.
I calibrated the TPS as such:
Disconnect negative terminal
Turn and hold key for 20s
Remove key
Connect battery
Put key in on position
Slowly press and depress pedal
Start truck
Same story
I replaced my IAC valve and didn't seem to help much. But If you adjust the IAC you obviously get different rpms because it's open further or closed further. Why this is adjustable is beyond me. That may be an issue.
What is really getting to me though is if I tap the top of the throttle body lightly with a wrench, the rpms all a sudden drop to 600, every time! I cannot figure how this is happening.
I do have a multimeter and any suggestions of what anything should be I can test them.
Thank you
Last edited by Mack8514; 07-19-2015 at 11:10 AM. Reason: title change
#2
#4
A couple of things. Make sure the connectors for the TPS and IAC are clean and tight. After that, I agree with '98DakAZ. Replace the TPS with an OEM unit. As he says lots of parts are just crap nowadays.
Also, check for any vacuum leaks on the throttle body or the vacuum lines connected to it. Any leak can cause an erratic idle. Since it does kick down when you tap the throttle body this is a possible issue. You could also spray some carb cleaner around the base and fittings and watch for an RPM change.
You did remove the throttle body and clean all the IAC passages completely?
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#8
I removed the IAT and the ohms climes after I pulled it out, as I researched it climbs as it gets colder