My 02 3500 has a buck or hiccup between 1200 and 1400 rpm
any thoughts?
Grey

 

Do you have a stick or automatic?

Do you have a power chip in it? Sometimes the aggressive fueling curve will do this at low rpm.

Sometime when it is hot out and with the A/C on the Injection pump will do this also.

Fill out your signature, it will help a bunch if we knew what you have.

.........Jim

 

Sorry,
it's an auto, no chip
Grey

 

When it's cool out and or not running AC it does not hiccup. What would cause this?
thanks
Grey

 

Do a code check see what comes up first.

 

Y2GREY- Welcome to DTR!
You are lugging the motor, IMO. Either tranny will do this at 1200 rpm..... but especially Automatics. Probably goes away when you add a little throttle .....No?

The problem - overdrive is a very tall gear ratio(.68). Great on the interstate at 70+ mph but I don't use it below 50 mph with stock tires.... or below 60 mph with my present 315/75/16's.

I lock out OD around town ... truck drives better, putting engine in the power band, and higher RPM does not hurt mileage. Also reduces smoke, if/when your add a little HP.

RJ

 

Yup, when I lockout the OD no issues at all, with the auto-OD and 3:55s I'm pretty tall