Having idle problems, HELP PLEASE!!

[srt10_Shipton]

Im new to Viper trucks and recently bought a 2004 RC. Ive had a few problems and i fixed them but still have a few ongoing or need to be fixed. I started having idle issues. It started when i noticed that when im coming to a stop and put the clutch in the idle would drop slowly snd hang at about 1200 rpms for a few seconds. Then my idle dropped from 750ish to 500 or under. Its hanging whenever i let off the throttle and dropping very slowly. I changed the TPS and that seemed to have worked for maybe a day. Next day it was doing the same things again. Changed the IAC and thst didn't help either so i tried the TPS again and tried adjusting the set screw for the idle a little bit and none of that helped either. Idle is hanging whenever i let off throttle, dropping very slowly, hanging at about 1200 before dropping all the way to regular idle rpm and sometimes itll stay at 750ish snd other times it ill drop to 500 or a little under. I have no idea what else to do and really need some help. Engine was just rebuilt a little over 3k miles ago along with the T56 tranny. Only check engine light is 0456 which has just come on. SOMEONE PLEASE HELP ME!!!

 

[trussman]

I have heard before that aftermarket sensors don't always like to talk well with dodge computers. It might be worth a dealer diagnostic fee to save a lot of parts swapping though. Welcome to the club as well

 

[VENOMOUS1 RACING]

Check your vacuum hoses under intake and under throttle body. They are getting old and tend to split at the bends or could just be off. Disconnect battery for about 10 mins touch positive cable to neg cable while disconnected to clear PCM and relearn TPS.

 

[trussman]

FYI that code is an emissions leak code. That could be the cause of it all.

 

[srt10_Shipton]

Check your vacuum hoses under intake and under throttle body. They are getting old and tend to split at the bends or could just be off. Disconnect battery for about 10 mins touch positive cable to neg cable while disconnected to clear PCM and relearn TPS.

I had the negative cable off of the battery every time i disconnected any sensors, let it disconnected for 10-20mins each time and then gave it some time before start up also. Stupid questiom but how exactly do you touch the cable together? Disconnect both and touch them together i assume? Vacuum hoses seemed fine to me each time i looked at them

 

[srt10_Shipton]

FYI that code is an emissions leak code. That could be the cause of it all.

That code is coming up bc i have catless mids on the truck. Its from the secondary o2 sensors

 

[trussman]

That code is coming up bc i have catless mids on the truck. Its from the secondary o2 sensors

http://www.obd-codes.com/p0456

 

[trussman]

This would be the downstream O2 code if I'm not mistaken.
http://www.obd-codes.com/p0420

 

[srt10_Shipton]

http://www.obd-codes.com/p0456

Youre right, my bad. Im not good with remembering which is which. Ill need to look into that one more. Ik it came up once when i didnt do the 3 click thing with the fuel cap.

 

[srt10_Shipton]

Check your vacuum hoses under intake and under throttle body. They are getting old and tend to split at the bends or could just be off. Disconnect battery for about 10 mins touch positive cable to neg cable while disconnected to clear PCM and relearn TPS.

Vacuum hoses looked alright to me each time i was looking or working in that area. I also always disconnected just the negative battery cable. Guess ill try disconnecting pos and neg and touching them together and see what happens. Im going to look into the vacuum line that runs to the evap system since its throwing that code.

 

[earl lee]

Do you have an A/M throttle body on our truck? Your symptoms are mainly related to the TPS/IAC though unless you have a different TB on that truck then I'd look there.

 

[VENOMOUS1 RACING]

456 has nothing to do with O2 sensors. It's a leak in lines from gas tank to leak detection pump. Small nylon lines.

 

[srt10_Shipton]

Do you have an A/M throttle body on our truck? Your symptoms are mainly related to the TPS/IAC though unless you have a different TB on that truck then I'd look there.

Just the oem throttle body on the truck right now but i just ordered a JTSVP throttle body but wont have it for a little while yet. TPS/IAC were just replaced in the past few days

 

[Slitherbeast]

small vacuum leak. keep looking. maybe smoke bomb test.

 

[Wifey]

Good luck! I beat that problem by not starting mine except for once every other year. Works wonders - J/K :rock:

 

[NukeGM/Ford]

small vacuum leak. keep looking. maybe smoke bomb test.

how is that done?? used to use carb cleaner around intake/head/carb mating surfaces on old cars looking for vacuum leaks, never heard of smoke test

 

[trussman]

how is that done?? used to use carb cleaner around intake/head/carb mating surfaces on old cars looking for vacuum leaks, never heard of smoke test

Banana oil smoke machine pumps it in.

 

[earl lee]

Check to make sure the elbow from the air intake is completely on the TB. It is possible to have the bottom cave inside the TB which would lead to a vacuum leak.

 

[Quicksilver Favela]

Clean the throttle body , mine would act the same way,

 

[srt10_Shipton]

Im waiting on my TB from JTSVP right now so ill see if that fixes it