i have a 2003 ram van 5.2 i have towed my camper for 3 years ( 5600#) with no problems this summer it started running hot i had a new radiator,clutch fan, therm. put in.Ran fine 2 months and while towing up hill it started losing power i toke it in and they cleaned the injectors put in a new o2 sen. a new iac ,new plugs,wires,dist cap,rotor,and checked coil,fuel presure.CPS, it runs ok until i step on the gas hard to accel. then it starts missing on 1 and 8 they shop i toke it looked at it for a week and cant come up with a solution does anyone have a idea for me to try?

 

Intake plenum gasket.

 

This TSB isn't supposed to apply to 2003 vehicles. But considering the symptoms you're having it's a cheap fix that's worth a shot.
http://dodgeram.info/tsb/1998/18-48-98/18-48-98.htm

 

is there any other signs of the intake plenum gone bad ?

 

i will try re routing the wires to see if it works

 

As Alloro stated above this is not supposed to apply to your van but here is how to test the intake plenum gasket:
http://dodgeram.info/tsb/2000/09-05-00.htm