Was driving down the interstate on my way back to Kentucky from Florida and noticed my rpm fluctuate while in cruise. This also correspondse to what feels like the transmission trying to go in and out of lock up. The transmission does not shift out of over drive. Just wondering if anyone has seen this before? By the way the truck is a complete dog now in overdrive.

 

Mine used to flux when i was going 60 around 2800RPMS and flux to 3000,3100 RPM....

I did the TPS cleaning and it went away, it also fixed my problems with my idle surging

As for it being a dog in O/D, mine has been since i bought it, I havent had overdrive on in a year....

 

this is common and caused by carbon buildup. Take a can of OMC engine tuner and sray the whole can into the TB of a warm engine. Let it sit for 6-8 hours and then idle it for 15 minutes before going for a hell-ride to blow the rest of the white smoke out.

others have used deep creep or 1/2 can of sea foam directly into the TB. Any of the tree will cost you $7.

 

i have a similar problem but it happens when im comming off the highway and i let off the gas completely it goes from 1000 to 1200 up and down up and down. its messed.

 

I had the exact problem and I replaced the TPS and it was the fix.

 

I should not have a carbon problem. The t/b is a Fastman that has only been on for about 2000 mi. and I cleaned all the sensors. I was thinking about just changing all of them.

 

My dodge dealer did all of the censor changes etc. to the tune of about a grand. They couldn't fix the problem so I had an independent mechanic look at it. His fix was the OMC stuff. The bill was something like $37 dollars... 30 for labor, 7 bucks for the can.

Report back the fix so it is in the inventory of repairs. Good luck.

 

A dog in overdrive, welcome to my world, you and me must be the only ones that have this problem. I have been told that it could be the TPS but im not gonna pull the trigger on that one yet, cause it costs like 50$$$$. ALso has your tranny been rebuilt????? If not it could be your torque converter or tranny slippin, letting the RPM'S fluctuate.

 

Where can you get a can of MCCC and do u know if it is sold in canada

 

Maybe the symptoms may help narrow your decisions.

While at HWY speeds with over drive and cruise controlon set at any speed 55 to 70 MPH, the engine would rev up 200 RPM and quickly return to the normal RPM. This occured about every 30 seconds.

When idleing the car in the morning in park, the RPM would spike up 200 RPM and then return to normal -600 RPM. The cycle was the same about every 30 seconds or so.

If I drove at HWY speeds without the cruise on I had no RPM flux. And of course this starting happening right after the 36k warrany experation. Good luck, let us know what the problem was.