Hey Everyone

I have a 2003 Dakota 4.7 SLT 2wd, it has 134,000 miles on it. The truck runs great, lately I started to notice that when I turn on the AC or Heat, the trunk runs a little rough. I can feel the bumble vibration in the steering wheel.

If I have the heater off, and start the truck, the engine is very smooth, turning on the lights, the engine is smooth, but as soon as I turn on the AC/Heater I feel what I described above.

So I change the plugs out, did not fix it, I took out and cleaned the IAC and that did not fix it.

I tested my gas mileage, and I am getting 13 MPG, I used to get around 17-19 at times.

Any thoughts?

Thanks
Mark

 

try some fuel system clnr mine used to to wanna die at night at the red lights with htr and lights replaced the IAC and alt and added lucas 2 days l8r runs fine

 

how old is the battery? a wild guess. if the bat is week the added load would droop the power making the ignition system run bad. for sure its a long shot.

 

Oh, I replaced my battery as well

 

Battery is about 8 months old now.

 

I am still having this problem, when I use anything electrical in the truck, ie windows, ac, lights, the truck will idle rough. I tested the battery with my ohm meter, and did the positive to the alt and neg to the alt and everything has tested okay.

I have 130,000 miles on the truck, so maybe it is time to change the coil packs?

 

you could take it to a local mechanic or advance maybe and have the alternator load tested, (having all accessories on). I too have around 130k on mine and i replaced alt, when my electrical got goofy on me, along with the IAC. My mileage was bad and my idle rough..I turned on lights and heater and noticed a drop in RPMS, did the reverse and rpms came up, which led me to alt.

 

sometimes the alt will still be good putting out power; but what goes faulty is the voltage regulator that's in them. Mine was reported to be bad. Shame I can't find a replacement like you can in some Fords; else i would just open it up and replace it. Looks like a new Alt soon enough.