Bobster999

Hey fellas,
I dont expect you to be able to diagnois this over the net but im asking for help if you can.
The truck has been sitting almost a year.
Crunk her up today and the engine runs good cold for about a minute.
Then a slight engine miss, and it keeps getting worse until it misses a lot.
When i give it throttle, after about 3000 rpm the missing stops and she runs great.
Have you ever had a similar problem?

Bobster999

No clue huh

fomoco998

Have you checked codes yet ? Fuel pressure checked yet ?

Bobster999

No check engine. battery was just reinstalled after sitting since last year.

marshallr

Old Gas is my guess

Bobster999

Hmmm... Maybe im wrong but i dont see how bad gas will burn good for a minute, then the engine starts missing progressively worse as it keeps running, then when i press the accelerator above approx 2500 - 3000 rpm the engine smoothes right out. I dont think gas burns like that.
Thanks for the guess tho...

David Young

Check your fuel pressure next, like fomoco998 said. Very common problem on our old trucks

Bobster999

So based on my symtoms, you think it may be fuel pressure related. Do you know what the pressure should be?

BLDTruth

Fuel pressure should be 35-45 psi. Any lower than 30 and the truck will not run properly.

There can also still be codes without a check engine light - check the top of the page to see the thread about testing for codes.

Things I would check first would be fuel pressure, the fuel pressure regulator (pull the vacuum line off of it and see if it smells like gas), vacuum lines to your EGR and fuel pressure regulator (all vacuum lines, really), and idle air control valve.

Bobster999

Thank you! this gives me some things to work with.