Engine/Transmission (1998.5 - 2002) Engine surge at 72 mph

[muskyman]

My 2002 just started to surge at speeds over 72 mph no cruise on rpm drop is hardly noticable, but you can hear the rpm change over a 3-4 second time. drop down to 68 mph no rpm changes. outside air temps are cold. Fuel preasure is at 10 psi, I will be changing the filter. Any ideas on the problem?

 

[MDobson]

Do you have to put additive in the fuel?

 

[muskyman]

No additives

Never seemed to need them in any of my dodges in well over 500,000 miles.

 

[bmoeller]

I'd start with the fuel filters.

I'm not using a fuel heater OR using additives in my '99. With the Attitude monitor, I have one spot set to watch the fuel temp. At least with the AD 150, the temp is actually going UP the longer you run it, even in below 0 temps. The poly tanks don't radiate the heat away like the aluminum ones do.

 

[monkeyman]

Is that fuel pressure at idle? What is at 2000 RPMs?
It could be many things, you did not say if it was stock or not
Rick

 

[muskyman]

RPM Surge

Everything is stock. 10 psi fuel preasure at 2000 RPM. The surging is RPM specific it happens at around 2000 rpms if you lock the overdrive out. this problem seems to be when you are maintaining the Rpms not when its under a load.

 

[turbo torque]

Do you have any codes? Could be the begining of the APPS going south.

 

[DEdwards]

Sounds like the torque converter is locking and unlocking

 

[monkeyman]

Or could be The TPS, if it has a weak spot, it would not throw a code,Also if you never replaced the speed sensor on side rear (drivers) they go bad with no codes. Mimics bad VP, all sorts of things. $13. 00 at AutoZone with life time warranty, takes five minutes. Change with engine off, do it fast as fluid leaks out. I am on my third one. I think its a one inch socket.
Rick

 

[RMecum]

I had a similar problem and the shop I took it too knew right away what it was... spikes of electric to the computer from the alternator causing the torque converter to come in and out of lock up. They put a ground wire from the alternator to the frame and problem solved!

The shop (Imler Diesel in Sacramento) had a kit already made up. Apparently it's pretty common.