98 1500, 5.9 Engine

I drove the company truck today, its slightly newer then mine, same size engine, it idles above 2k RPM, I think maybe 2.2? Then the other day my buddie was drunk and I had to drive his *** home, was his truck, it too was a dodge, not sure of year, 2000 maybe? Anyway, his truck was idling 2kish also.

I naturally watch my RPM all the time conserving on gas, and it idles at 1.8k RPM, why is mine so much lower? Is it because of 37 tires on stock 3.55 still?

This was all on freeway doing 70ish. When I say idle, its when you let it settle out and just cruise, dont know what word to use. [What do you call it?]

Think I know the answer, but double checking with you guys.

 

Idle is engine RPM sitting still with foot off accelerator.

 

Yes it is most likely due to the size of your tires.

And I believe the expression you are looking for At (insert Speed here) my truck runs at (insert RPM here).

 

I got 265/75/16s on the back o mine, 3.55 gears, and I spin about 2100 doing around 70...