5.7 350ci - i have a 1989 with a 350 when the truck is cold it idles up and down for about 30 seconds then it will idle smooth when ...

i have a 1989 with a 350 when the truck is cold it idles up and down for about 30 seconds then it will idle smooth when you go to drive the truck it spits alot mainly when you try to pick up speed iv replaced alot of stuff and still havent found the problem

THINGS IV REPLACED
fuel filter
IAC valve
MAP sensor
EGR siloniod
EGR valve
TPS sensor
PCV valve
it has new plugs as well

nothing has fixed it iv even ran gas treatment and seafoam in it


HAS ANYONE ELSE HAD THIS PROBLEM OR ONE SIMULAR TO THIS?? AND HELP IS APPRECIATED

THANKS!
jason

Have you had your fuel pressure tested?

no i have not iv been looking for someone to test it for me is there a way i can do this myself?? and if there is what all will i need?

You can buy a gauge at most auto parts stores, it just plugs into your fuel rail next to your intake and you turn on the key to see what your fuel pressure is. Kinda acts like a Tire pressure tool. Fuel injected engines usually need about 60 PSI of fuel at all times running to the fuel rails. If that checks out ok, Then I would find someone with a High tech scanner and it will be able to tell you if each injector is working right and at what pressure. I know the guy in town I take my trucks to, he charges something like 40 bucks per scan. So make sure if you do take it to someone to have him scan for everything, that way you aren't making multiple trips and spending extra money.

my doestn have fuel rails its a 89 it has a throttle body that looks like a carb..... it has 2 big injectors sitting in the middle of it and they are both sprying fuel good and the same amount i know there has to be a way to check the fuel pressure on it but im not sure how

Your O rings might be bad and not shooting fuel correctly. You can buy a kit to redo it yourself pretty cheap

Re: running rough HELLLLLPPPP!!

After having fuel pressure checked I'd go back and change the fuel pump and make sure float is adjusted properly. Also check for gasket damage.