Hey guys,

So I threw the Fastman TB back on the truck, and the high idle issue has returned .... but this time Im finding it. I already replaced the IAC, but I was told this was probably the problem again, so I bought another one. And it still didnt fix the problem. I am finding no vacuum leaks that are on the top of the engine, and the idle problem doesnt happen all the time. Normally after a 10-15 mile drive, when I go to put the truck in park the RPM will go to about 1200. Sometimes if I rev the engine, when the revs come down again the idle will be normal.

I was looking any sensor values on the Superchips today that would tell me vacuum. I didnt find any of those, but I found the EGR %. With the engine not running, the % goes between 0% and 7% very rapidly. After startup, its at a solid 7%. I havent checked what it is when idle is normal vs when its acting up. But shouldnt the EGR % be at 0% or completly closed? My idle is also rough, even on Premium gas with the 91 performance tune and the NGK 4644 plugs.

Sounds like a bad EGR possibly? Im thinking it may be disfunctioning so little that the CEL wont trigger, and the Fastman just brings out the problem where the stock throttle body can cover it up.

 

Could someone with a Superchips or a logger that will read real-time sensors do me a favor? Im looking for the % value of the EGR Com at idle and with the engine off(ignition in on position). I need to know if its reading 0 or a different value, as this will tell me whether the EGR is creating a vacuum leak for me or if the 7% Im getting is normal.

On your SC youll need the Data Logging ability (downloadable for free)
You will find it under - Data Logging - Advanced - EGR - EGR Com % and then select "Start Display" It will take it a second to start showing the values. The ignition cannot be in the OFF position. Im looking for the value for the EGR Com. % but anything you can provide would be awesome.

Also, while driving, the "EGR % Err" is flashing from 0.00% to 99.22%, so Im not sure if this is normal either.

 

I was getting the same value at idle and also the 0.00 - 99.225 error so that must be normal.

 

Thanks alot, Kent! I appreciate it a ton! I was telling the guys at the shop that it may be the EGR, so atleast we can leave that out now. My next guess is the intake manifold gasket .... but it really could be anywhere. They will probably be doing smoke test. I have it in for rear brakes and they will be looking for the problem after that. They still think its the throttle body, but Im thinking theres a micro leak somewhere and the bored throttle body just brings it out while the factory throttle body can cover it up.

As a side note, I set the truck back to stock while I was bored at school today and that 15 mile drive home sucked. I felt like I had to put my foot through the radiator to get it going .... AND THAT SHIFTING SUCKS!

 

lol....i'm putting mine back to 87 tomorrow...premium is back up to almost $3 a gallon again...hope it don't mess anything up going back and forth between tunes...Confuse the computer or something....lol

 

Nah, you'll be fine. Ill probably be putting mine back on performance as soon as I get in the truck tomorrow when I go to pick it up. I cant stand that sloppy shifting from Dodge.

 

Rengnath, I know you said you replaced the MAP sensor already, but my 2005 started acting exactly the same as yours. I cleaned the TB out well, no difference (I would start the truck up and the idle would jump to 1600 RPM and then gradually come down to 800.
It seemed to only do it when it sat overnight. Everytime I reset the computer, it cleared up for a day or two. I had the ECM flashed, no difference. It idled rough (not smooth like I think it should be). I totally ruined the MAP sensor cleaning the oil slime off of it.
Once I replaced the MAP with a new one, it runs and idles like a top now.

Maybe worth a try again for $20.00 or so? Also, a friend of mine had a similar problem on an older Dak, turned out to be his temp sensor!

 

I will gladly try both of those if they cant find anything at the shop tomorrow. I already dropped $90 on another IACV from the dealer this time and that didnt work. And electronics arent returnable.

My MAP sensor wasnt too bad, but I threw the new one in and it didnt help my idle. Would my temp sensor show anything different on the temp gauge? Or is that something that I would never even know was bad?

 

I will ask him tomorrow the specifics of the problem he had.

 

Thanks Hammond,
I appreciate it.
This problem needs to get solved. Ive dropped hundreds in to this "bored throttle body" project for my truck.