89 D150 318 TBI auto

Symptoms:
When I start it up it idles normal. If I give it a little gas it wants to stall and then the idle raises and lowers over and over then will even out or stall. Before I had the engine rebuilt I checked the cam lift and it was way under spec. And being that the engine had 300k miles on it I had it rebuilt. But to my surprise I guess it wasn't the camshaft after all and it's having the same symptoms. I haven't been able to go seat the rings because of the symptoms.

Before the rebuild I was able to move the truck to my new place(thankfully with a 2car garage) by just flooring it all the way and putting it in neutral and reving at stoplights. But I still stalled a couple times. Was sketchy.


I checked the flash codes and I get a 3-5-5. I know 5-5 is to signal the end of the codes but 3 is not listed.

I wanted to check the vacuum because it was weak before the rebuild. The vacuum is vibrating rapidly between 15 and 18 in. hg.

Fuel pressure is at 15 with the fpr vacuum hose connected but the fuel pressure doesn't go up when I disconnect the vacuum hose. So I check for vacuum going to the fpr and there is none. But when I pinched the return line I saw the fuel pressure go up.

If anyone has any ideas I would be grateful. Very discouraging not being able to figure this problem out. Here is a link to the other thread I had going for further info but I think I covered it here.

https://board.moparts.org/ubbthreads/show...c=1#Post8431444