I have a 1990 ford mustang 2.3 lx and I am having a major problem! Last night I was driving and all the sudden It felt like I lose lots of power! I brought my car into my friends shop to look at. First thing we did was check if it had spark and it did so we changed the spark plugs and it dixnt change anuything and if you let off the gas at idle the car will die neecx help! Thanks

 

Sounds fuel related, I'm not familiar with the 2.3's, but does it run at all? Could be fuel pump, fuel filter, or is there fuel in the tank? Gotta ask lol.

 

Yea it does if you put the booster pack on it and there's half a tank

 

Did you look at the plugs when you pulled them out? Did they all look the same? The ideal plug will look light brown after running for a while, black or greasy would indicate one cylinder not firing. White indicates it's running lean. Did you check the plug wires? If they are original, they should be replaced.
I'm guessing it's a vacuum problem, did you check all of the vacuum hoses? (these are small black rubber tubes)

 

Yea check vacuumm lines all good but cylinder 1 and 2's spark plugs were much blacker then 3 and 4 as they were a light brown! So is it the distributor cap and rotor??

 

Could be, did you run a compression check? Could be worn out valves or rings. What does the exhaust look like? Any blue smoke?

 

If your getting spark, most likely cap and rotor are fine for now. When it dies at idle, does it just stop like you turn the key off, or does it try to keep running with a spit/spudder?

Have you checked fuel pressure?

And like Chrome stated, sounds like a vacuum leak to me.

Keep us posted

 

Does smoke blue at all actually and now it just dies once your off the gass

 

Doesn't sorry about that! And how do I check the fuel pressure? Or check for a vacuum leak?

 

Vacuums leak are easy to check for, get a can of starting fluid and spay it near the leak. The engine will speed up when you are near the leak. You should start by visually checking all of the small rubber hoses.
You may have a leak in the intake manifold where it bolts to the engine. Be careful with starting fluid, it's extremely flameable and the fumes can put you to sleep. I'd look for something near 3 and 4.