Hi Guys, So on the highway in my 98 Ram 4x4 5.2L V8, I would get above 50, the eng. would make some straining noises like it had no power, then the check eng lite would go on. When I got off the highway on the back roads (30mph) the light would shut off and the truck would run fine. Took it into the shop, he said the only code that came up was a misfire and everything else checks out. He is doing a tune up overall right now. Has anyone else delt with somethinglike this? Thanks-

 

I bet your cat is plugged. Have that pressure checked before replacing any ignition component.

 

Thanks Wand, Got the truck back today, seems to be running a lot better- I have yet to open it up on the highway to see overall.