Having a problem with my idle hoping someone here can help. I have a 2001 ram 5.9 stroked to a 408. It has a 58mm F&B throttle body on it. Having a problem with the idle surging a bit. I replaced the TPS when I installed the throttle body a few weeks back. The IAC I transferred over from the old throttle body but it was new not long before that. I disconnected the battery to clear the pcm and set the throttle blades according to TPS voltage at .66. Problem im having is when hitting the gas as the rpms come down it starts surging a few hundred rpms. I have a Cam with some lope so I cant get a steady idle but it never surged. I used factory mopar parts but im thinking maybe the IAC is bad and the TPS is trying to compensate for it. Anyone ever get bad mopar parts? Only Vacuum coming off the engine is the PCV, Brake booster and the line to run the heater controls. I have locking hubs on the truck so all the vacuum to the tranny is gone. I pugged the heater controls off at the manifold with a cap to make sure it wasn't that. I ordered a new Delphi IAC which is coming tomorrow just to see if that helps. Im stumped. Any suggestion would be really appreciated.

Thanks again in advance

 

Running all the upgraded parts you need a tune to tell the PCM they are installed. Do you have a scanner that can read live data?

 

Sorry I should have added, Im currently working with FRP (Flyin Ryan) for the tune. I already loaded the base tune he wrote with all the upgraded parts. I am now doing data logging with him. My scanner doesnt read IAC counts and for TPS voltage I was using a multimeter at the plug for voltage. The truck is running ok, I still have a bunch of data logging to do as we only just started and he likes to keep it low rpm at first. I spoke with Bruce at F&B and he mentioned setting the throttle blades using TPS voltage between .54 and .74. So im at .66 it seems to idle ok but the recovery from throttle is where im having the problem.

 

I read a couple posts down from this with someone having a similar problem. One person replied it took them 5 tries to get a good IAC (Aftermarket). Mine is MOPAR, which is why im wondering is anyone has installed a Mopar part and found it to be faulty out of the box

 

That's a possibility many people have gotten bad parts out of the box.

 

Im sure but at 75 dollars a sensor im not willing to play the roulette wheel with mopar. The Delphi one is coming tomorrow so hopefully it fixes it otherwise Im stumped.

 

I am being you need a tune

 

Im sure Ryan has seen my set up 1000 times. He wrote the base tune with all the parts incorporated as I said above. I already data logged up to 2000 rpm and he revised it once already. I dont think its a tuning problem. At least I hope not.

 

I missed that info I was under the impression it was the stock tune