p0251 had that before about 2-3 months ago.

got a new one p0370

i was turning the truck on and off multiple times when the codes occur, would that have caused them.



is this a bad thing i need to start saving my money for.

i had just gotten done with a 70 mile trip with no prolems about 20 mins efore that

Bad connection on the the top Injector pump optical sensor harness. You shouldn't have one on a 98, but just in case, look to see if there is an optical sensor filter harness.... sometimes they fail causing bad connection and bad singals to ECM. You end up in a limp mode with those codes, or at least I did. Try unplugging and replugging the connection first, see if that buys you anything.

I had p0370 and p0251 together on a 97 'S'...an OS R+R fixed it...

what does the optical sensor look like? would a bad pmd ground cause the problem. my ground for the harness is not on the pump anymore

Six pin plug that goes on top of the injection pump.

what does the optical sensor look like? would a bad pmd ground cause the problem. my ground for the harness is not on the pump anymore

Which begs the question, "what did you do with it?"

That ground should be back on top of the IP - it can cause strange things when it's removed. I don't know why some of the PMD-cooler guys want to move it, but they do. Potential quick fix - put it back and see what happens.

well the ground i relocated to where i mounted the pmd origanally got the idea from pmd sellers then i got a new pmd and relocated it to a much better spot but left the pmd ground attached to my old pmd mount