Have had this truck for 5 years and this is the first problem I have had with it. About 2 weeks ago it started to spit and sputter a little when accelerating but would pull out of it quickly. Progressively got worse over the next week to a constant sputter and die situation. so I started replacing parts. I assumed It was the fuel system that was the cause so I replaced the fuel pressure reg. Then the Map sensor, The high pressure fuel pump and also the TPS. Oh yah! When I replaced the high pressure pump the thing ran OK for 2 days after! but now is back to a non start condition.( Im sorry) will start but dies right away and is sputtering constantly. My question is, could this be something other than the fuel system? Maybe a Cat converter restriction?

I think you hit it on the head I think it's the cat it can't breathe

Is there a rotten smell when it is running?

Do you let the truck idle much?

Did you replace the fuel filter?

:headscrat I'm figuring since we replaced all these other parts & haven't fixed it, were limited on test eqiupment. Th first thing you need to do is hook up a fuel pressure gauge & see what the fuel pressure is. I don't know the year, but if it is between 86-96 it needs to have 35-45 psi. If you don't have a gauge you can pick one up cheap at Auto Zone. You will save money by buying tools & not all the parts. You could have a low pressure fuel pump failing, or the new high press fuel pump could be bad. You could have a voltage issue or a fuel filter plugged. This is what I would suggest. :fordsym:

There is no "bad" smell but I can smell gas sometimes when its sputtering and after it stalls. Thats another reason I was drawn to the fuel system. Replaced the fuel filter when the pump was installed and no I dont have much in the way of test equipment but I will check the fuel pressure. This truck has duel tanks that lead into a small resevior mounted on the rail just behind the high pressure pump. I guess its purpose is for steep inclines when the fuel tanks are low if the in tank pump hits air the high pressure pump draws fuel from this. Its also to switch from 1 tank to the other. Does anyone have any knowlege of this thing? Is there a screen or a filter inside the unit? My manual doesnt tell me much. Thanks for your input!

Well the resivoir you are talking about very well could be for a reserve so the high pressure pump does not cavitate. It should not have a strainer or filter in it. The intank pumps will have strainers & there will be the in-line fuel filter. That should be all. If it does not change at all when the tanks are switched, I would say it is not the in tank pumps. Get a fule pressure reading, that will tell the tale. :brainflos

CHECK YOUR COIL PACKS THEY SHORT VERY EASILY CAUSING IT TO RUN ON LESS CYLINDERS IVE HAD A PROBLEM IDENTICLE TO YOURS AND THATS WHAT FIXED IT

A little late, yes, but hopefully your advice will still be able to help him out! :)

And, welcome to CF!

I had same problems with my 89 f-150 and replaced the ICM on the distributor, it was bad and fixed the problem.

Check your pickup in your distributor. I had a similar problem on my 1985 f150 with the 302 v8. I replaced a bunch of stuff, even the intake gaskets. Turned out to be the pickup, usually a GM problem. Also you could check your ignition module. Some parts stores may do this for free.