The truck has hesitation accelerating. If I go up a hill it will slow down to almost a stop. On the highway the rpms will jump up and down around 40 mph and will buck slightly or surge. It seems as if its downshifting. The truck has no low end power.

Things I did, new plugs and wires, cap and rotor, seafoam.

I'm thinking tps or map but I'm not sure. Is there a testing procedure for these? Or do you have any idea what the problem could be?


88 f350 460 fuel injected

 

Get another fuel filter, change it, and drain the old filter out the way fuel was pumped in.
What comes out will answer some questions like , water , dirt etc. If you have a hard time blowing through the old filter the direction the fuel goes through that will tell you a lot .

Also make sure the EGR valve isn't sticking partially open.

 

I did do a fuel pressure test.

How would I check the egr?

 

Fuel pressure in this case is only half the test. The other half is the fuel volume and a pressure gauge will not always reveal that problem. If you haven't done it yet I would change the fuel filter.
With the engine idling lift up the pintle on the EGR valve and the engine should falter or stall. What you can try would be to remove the vacuum hose from the EGR valve and plug it. Then road test the vehicle and see if there is any difference in performance. If it improves that would suggest too much vacuum may be getting to the valve at the wrong time.

 

I just did the old school engine scan and codes 24,67,81 for KOEO ,14,19 for CM.

24 ACT. Would MAP sensor fix this? Or is this failing on its own?

67 NSS. The reason I havent bought this yet is because its special order and I dont know if I have electric shift or not?

81 MAP. This looks to be the cause of the problems.

14 PIP. Not Sure about this?I did replace the cap and rotor. This would be the distributor or maybe install error?
Quote:
Two or more successive erratic Profile Ignition Pickup (PIP) pulses occurred, resulting in a possible engine miss or stall.
29 VSS. This makes sense for the problem shifting but at the same time I read the map can do it too.

So I'm going to pick up the VSS and MAP. Not sure about the other parts yet. Any input would be appreciated.

 

This is what I would do.
Clear all the codes!
Do the Key on engine off test again and repair those problems before I did anything else.
After I was able to get a code 11 for the KOEO tests then I would do the KOER tests and correct any problems there.
My Continuous Codes are intermittent problems that I would search out last.
None of my code info says anything about a questionable MAP sensor.

 

Did the MAP, theres improvement with power and going up hills. I still have the engine shake and what sounds like misfires at 30mph +. I'm assuming that's related to the distributor.

 

There is a pick-up coil in the dist. That's where your PIP signal originates. Sometimes a poor ground connection in the dist is a problem.

 

is that something I can see by eye? The current cap and rotor is warrantied. I could swap it out before I spend on the distributor.

 

You should be able to see it , but Usually we always confirm a part is defective before throwing money at it and just changing parts.