I have a '99 Durango 4WD with about 105K mi. The thing starts and runs very smooth... except for when its in overdrive at about 45 mph+. It is vert sluggish, hestitates almost like a misfire. On the highway, it cannot maintain 60-70mph up a slight incline without it downshifting into passing gear ...running cruise control is impossible!

At 80K mi, the dealer replaced the PCM changed under warranty due to the engine just shutting down on its own. We have checked cyl compression, fuel pressure, exhaust backpressure, replaced plugs (twice), cap, rotor, wires, coil and TPS. [Note: the problem really seemed to be noticable after the factory PCM replacement.]

The computer throws no diagnostic codes to narrow this down for me, so this is really frustrating. Any adeas would be greatly appreciated!

Thanks....

 

What RPM are you running at 65 mph? A 3.55 gear ratio could explain the shifting.


The dealer could have installed the "Death Flash" as an upgrade and that could cause the issue as well.

 

if he flashed your computer , he put on the deathflash, which retard your timing, which kills your performance and MPG , i installed a superchips to overwrite it and it runs like beast now .

you could also have a plenum leak which will hurt your performance also , look down in the throttle body for oil , if you have oil its leaking

 

I'm running about 2,000rpm at 65mph. But as mentioned, it can't hold that with a slight incline. It's worse with the AC running.

What's the best way to have the PCM reflashed? Can it be done by a local tech? Or, I've companies that require them to be removed and sent to them.

Thanks guys... I appreciate the input!

 

Just buy a superchips tuner and it will over ride the issue.

 

the tuners are the best/simplest/most effective way of solving the issue, no down time and you can undo it if you desire later

 

yes , SCT is a custum tune that deletes torque management superchips does not sct is the best out there for mopar

 

SCT take tuning to a different level but you pay for it.