hey guys, I posted this problem before thinking it was possibly my high flow cat causing this problem of having my rpm stay near 2000 while cruising around 50 mph.

for all the 4.7ls out there you know normal at 50 mph is more like 1400 rpm. the rpm stays high only when cold outside. any ideas why this is?

after about 5 miles of driving or so she drops back to normal rpm when I'm at speed.

So basically this is what she's doing:


Cold morning, shes been sitting over night in a garage. cruising speed is around 50 mph and rpm is around 2000.

After about 5 mins (realistically 5 mins) or 4-5 miles of driving she starts to act normal. mostly...

Any ideas guys? when shes cold her rpm are high. once the engine is warmed up some she acts better.


I'm getting around 10.5-11.0 mpg right now instead of my usual 12.0-12.5 mpg or so in the winters. which has put a big sore on my wallet.


thanks guys.

 

Sounds to me like you could have some crud on your O2 sensors, I'd recommend unscrewing them and taking a torch to them to burn off the suspected residue. Also it sounds like you could have a bad TPS (located on driver side of TB).

I'd take a reading from it and it should be in the ballpark of .70 to .75. Anything higher than .78 I'd suggest replacing it.

 

sounds to me like the truck just needs to warm up and the transmission fluid needs to get up to temp before the tc locks up, might be time for a fluid change.

 

both of those sound like good ideas. I'm leaning more towards the o2 sensor may be dirty, and the tranny fluid needs changing.

Any other ideas guys?

 

Sounds to me like your transmission is staying out of over drive (4th gear) and it should do this when the trans is cold (about 30-35 F). Basically it's staying locked out until the trans warms so you don't burn your overdrive out and this is normal.

 

I see, well its been fluctuating temp wise here in Minnesota. this morning it was around -12 degrees and right now its around 0 degrees outside. yesterday was slightly colder. its been on the cool side but its been doing this for a good few months now.

 

Man, I just moved down to the Tampa Bay area of FL, and it was 63 this morning and got up to mid 70s during the day! Moved from TN so this was a huge difference from snow and freezing temperatures.

Its nice seeing something a little more warm.

 

yeah, i cant wait for the winter to be over. I'm done playing in the snow. its just getting old now.

any ideas what the groundhog said for spring? lol

 

He didn't see his shadow, so spring is near!

 

That sounds like great news to me! cant wait til its 60 degrees and i can just throw on a hoodie and roll my windows down and roar past people. gotta love the fall/spring season. not to hot not to cold. i'm tired of minnesota weather. it gets as cold as -20 degrees AIR TEMP and as hot as 100 degrees with humidity.

thats to much for me.


edit: just checked and it says in Minnesota it can get as cold as -60 degrees below (with windshield i'm hoping!!!) and as hot as 114 degrees. both numbers seem far-fetched.