Ok, so recently every time i start my truck it will start with a longer than normal crank then run fine for about 30 seconds and then it will go into a really lopey idle. IAC valve is also fully open during this, as i can easily hear it. If i press the gas during this idle the truck will rev up and hold a high rev (around 1500rpm) for a couple seconds and then go back to a normal RPM and continue the lopey idle. If i don't let the truck warm up for at least 15-20 mins and start to drive the truck will sometimes give no response when i press the gas pedal, unless i mash it. Sort of feels like its chugging. However it gets better as i drive it. Are we thinking fuel pump here? Or more in the direction of sensors, wires, cap, etc.


Truck is an 01' dodge ram 5.2L 108k. 180 T-stat

 

Cleaned the IAC well lately? Plenum been done? Vacuum leaks? How old are the O2 sensors? Have a scanner that can read data?

Checking fuel pressure sure wouldn't hurt any.....

 

Haven't cleaned the IAC, but am about to order a new one. Not sure if plenum is blown or not but i have the parts to fix it sitting in my room. Just need to find time to do it. O2 sensors are stock as far as I know. And yes I have a scanner that reads data, what would I be looking for?

 

I just had this issue with chugging and getting better as I drove. not so much the idle symptoms. it was my O2 sensors and didn't throw a code.

 

O2 sensors actually start influencing things after about two minutes of run-time. If it's fine for a couple minutes (from stone cold), and then starts acting up, yeah, good chance the O2 sensor is the culprit. If it runs like crap from the get-go, check fuel pressure first, and see what it looks like. (need a gauge, PCM doesn't know.) Should be around 49PSI at idle.

When is the last time the truck had a tune up??

Don't use generic sensor on these motors. They just don't like them. Get *Real* dodge parts.

 

Prob 20,000 miles ago as far and cap and rotor. Plugs are prob 5,000 miles ago not even. And yes it runs fine from stone cold for like a minute or two and then starts to act up. Could very well be the upstream O2. And yes I also use MOPAR and OEM parts and far as electronics go

 

unplug the front O2 sensor, and see if your issues go away.

 

Sounds like a plan ill keep you updated

 

Inquiring minds.....

 

Well today I unplugged the o2 sensor and the issues went away... Now just gotta find out a way to get it out with out having access to a torch