This is for a 2004 Ram 5.7L. I have to put my foot on the gas to start it and keep my foot on the gas. I thought it was a clogged CAT. I had the engine codes checked and it came back with "multiple misfires and open circuit on injector 8" so I replaced injector 8. That didn't help. Checked codes again and it gave O2 sensor before the CAT on the drivers side. I popped the exhaust loose from the exhaust manifold and it fired up okay. I replaced the CAT on the drivers side and it still didn't help. What else could it be? This is driving me crazy and I have to get it running by Saturday. Any help would be appreciated.

 

A failed PRE-CAT O2 sensor will wreck havoc with the PCM, did you replace that sensor?

 

I did replace it but it did not help. I know the 2004 5.7 does not have an IAC. What takes it's place? I pulled the air intake off and noticed that when I step on the gas, the throttle body barely opens. Is this normal for this truck. I am used to working on an '85 IROC Camaro and when I punch the gas the throttle opens up but it is cable driven.

 

Sounds like it could me the throttle position sensor. These things are drive by wire. Does it have any power when it is running? With as many electronic systems on these trucks as there are, any number of systems or parts could effect something seemingly unrelated or even cause a seemingly catastrophic failure. The only other things that I can thing of are to check the fuel pressure (fuel pump and filter might be going bad), check the MAP sensor in the intake, do a basic tune up, seafoam it, and take off the belt to see if any component seems to be dragging more than usual. Hope this helps!

 

I had the same problem with my Acura.... it was the TPS switch (throttle position sensor). The switch could be broken. Worth a shot..

 

I had a problem with my 04 5.7l and if sounded like what your problem is, mine would die on me sometimes also. The truck finally threw a code and I took it to an AutoZone to see what it was and mine was the EGR Valve. It wasnt to much and easy to install.

 

look for an exhaust leak in a weld somewhere between the 1st and 2nd o2 sensors on that side ...i found an exhaust leak in mine and it may sound crazy but it was doing the same thing...i have after market cam with a cam tuner..and after i got the check engine light to stay off i was able to reset the pcm and adjust the cam tuner to right position to make it run right..as hammer said..these o2 sensors play hell on these pcms

 

I am having the same issue. Any fix? I recently installed a new TPS, could it be bad already or it sounds like a new EGR Valve could do the trick... Just wanted to see if jfreeman74 got it fixed...

 

Mine was the IAC... $220 later... ouch.

 

Where is the IAC? Pictures?