bad miss at full throttle

[95greenghost]

I have a 89 ranger 2wd with the 2.9 it takes a while to start but when it does it idles fine. the problem is when the petal is three quarters to full throttle is cuts out or bogs way down but when it is back under half it runs fine? it has new plugs, wires ,fuel filter. any ideas?

 

[86oilburner]

o2 sensor or cat plugged up?

 

[95greenghost]

Any way to check either 2 be sure cuz they are both kinda pricey or could it be something else? The truck sit for 2 years and i just got it.

 

[Mysticcook]

There might be other ways to check this I just took mine off. did it yesterday so first thought that came to mind.(lifted motor to remove oil pan to check oil pump, bearings)

drop your exhaust right before cat should be three bolts. using Pblaster (great stuff) hope they come off but you can grind if worst case.

I had to on top bolt but I also have a 3" body lift so lots of room!!!!!

 

[Mysticcook]

Another idea, you didnt mention cap and rotor take off look for cracks etc fine carbon black lines and or moisture. 2 inch body lift makes getiing back there so much easier really makes removing tranny almost enjoyable.

 

[IMenriched]

could be several things ...best to get codes 1st to get a better idea of what going on

 

[95greenghost]

think it might be the fuel pump! It had no codes wrong and the pressure gauge looses pressure when you turn the key off. You have to prime it 5 times to get enough pressure to start it. What you guys think?

 

[Mysticcook]

Hmmm! not real familiar with the fuel system. But if your losing pressure I would wiggle your gas lines before it enters fuel rail. Thats how i found a excessive fuel usage a line was cracked. eek .The in gas tank fuel pump is only like 10 psi?(i could be wrong) than the high pressure pump bumps it up to 30 to 40 psi.
I looked multiple times for my fuel leak but never when it was running.I never noticed the gas dripping i guess!!!(thinking it was something else)

 

[95greenghost]

does the 89 have a high pressure fuel pump the only one i know is the one in the tank?

 

[95greenghost]

Problem found!!! Put an new fuel pump on it and it ran like new, must have been the check valve!