Truck wants to die when I hit the gas

A

Art5

New Member
1994. pushrod 4.0. Manual 5 speed. Truck sits there and idles well. when i hit the throttle she runs like crap, acts like it wants to die. Anybody have any clue why my truck might be doing this? this is my daily driver right now so I really need to get this figured out asap. Any and all help is greatly appreciated.
Thanks,
Art
 
Can you come on the throttle slowly and let it build up rpm or does it not matter how fast/slow you hit the gas? Id check your fuel pressure.

Im not great with gas engines, more of a diesel guy myself but I will help ya as best I can
 
kanuck15 said:
Can you come on the throttle slowly and let it build up rpm or does it not matter how fast/slow you hit the gas? Id check your fuel pressure.

Im not great with gas engines, more of a diesel guy myself but I will help ya as best I can
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Yes i can come on the throttle slowly and let it build up rpms.

I found an injector o-ring that was leaking fuel, put a new one on, and now im having different symptoms. At idle it will miss intermittently, if i throttle up and then let go it backfires. when i hit the throttle it still runs like crap but not as bad as before. Fuel pressure test said 28 with vacuum line attached, 38 with it removed. it is a harbor freight gauge so idk how accurate it really is.
 
28 seems rather low. It should be 40 or so?

As far as the miss I would look for a vacuum leak. A backfire is a dead give away of a vacuum leak. Could also be the fuel pressure issue
 
kanuck15 said:
28 seems rather low. It should be 40 or so?

As far as the miss I would look for a vacuum leak. A backfire is a dead give away of a vacuum leak. Could also be the fuel pressure issue
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I just fixed the only vacuum leak I found a couple of days ago...let me check the chilton for what the fuel pressure should be...and like i said i'm not 100% confident in the accuracy of my fuel pressure gauge.
 
Here's what the chilton says:
1993-1997 models
Key on, engine off 35 to 45 psi
At idle, vacuum hose connected 25 to 35 psi
At idle, vacuum hose disconnected 35 to 45 psi
 
And here's what my test read:

Key on, engine off 37 psi
At idle, vacuum hose connected 28 psi
At idle, vacuum hose disconnected 38psi
 
I went and bought a MAF sensor, turned the truck on, and.....big difference. I can rev it up and everything I just drove it around. if i really whomp on the throttle and let go it will still backfire but it runs and drives thanks a million to everyone who posted on here to help me.
 
Art5 said:
1994. pushrod 4.0. Manual 5 speed. Truck sits there and idles well. when i hit the throttle she runs like crap, acts like it wants to die. Anybody have any clue why my truck might be doing this? this is my daily driver right now so I really need to get this figured out asap. Any and all help is greatly appreciated.
Thanks,
Art
Click to expand...
Have you checked maf,how was it running before,I've got the same truck with auto.
 
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