89 2.3l LX Rough Idle/Stall

Hello forum, first timer here working on a 'stang that needs some TLC. Have a couple of questions for you all if you can help me.

As stated, I have a 89 Mustang LX hatchback, 2.3l 4 banger. I just bought it from a friend, and it ran decently until I got it home and decided to tinker with my new toy; I changed the spark plugs which were in dire need of it, performed an oil change, replaced the drive belts, and the battery terminals . One of the old terms had a penny jammed in there for conductivity and to keep the worn terminal tight.

Now, as I said, the car ran decent, aside from the present smell of fuel. The catalytic converter (obviously old) did happen to release smoke after I shut the engine off, but now I can't figure out what may be the problem that I have now; the pony turns over with ease, but give or take 15 to 20 seconds, the engine decides to drop down to 1500 RPM, and begins to buck and idle like a tractor on a bad day. From that point on, the car either stalls out, or slowly picks up back to 2000 RPMs and a relatively smooth idle, depending on what it wants to do. When I get it out on the streets, the acceleration is poor at best, and loves to stall out at an intersection, or a stop sign. I have also noticed a stronger fuel aroma, and there is a slight smoking coming from the exhaust (I cant precisely tell what color, with being so faint).

Also, for another point of interest, just for laughs, I realigned the spark plug wires (shortest to longest) and reattached them, to which the pony ran a bit better, but still idles rough or stalls.

Any ideas, fellas?

Welcome to the forum LMaruko. How long did the car sit before you bought it? Does it have fresh gas in it. Did you set the plugs to the correct gap? If it ran good before you started working on it then more then likely it's something you did to it. On a car this old you should replace the air filter and spark plug wires also. A clogged air filter will richen the air/fuel mixture which could be why you see smoke and smell gas. Broken spark plug wires won't allow a good strong spark at the plug which could cause a rough running engine and incomplete burning of the air/fuel mixture. Also check all of the vacuum lines for leaks (cracks) or loose connections. Old vacuum lines become brittle and may not fit tight on the connections-maybe you knocked one off. There's a few things for you to check-good luck.

Welcome to the forum LMaruko. How long did the car sit before you bought it? Does it have fresh gas in it. Did you set the plugs to the correct gap? If it ran good before you started working on it then more then likely it's something you did to it. On a car this old you should replace the air filter and spark plug wires also. A clogged air filter will richen the air/fuel mixture which could be why you see smoke and smell gas. Broken spark plug wires won't allow a good strong spark at the plug which could cause a rough running engine and incomplete burning of the air/fuel mixture. Also check all of the vacuum lines for leaks (cracks) or loose connections. Old vacuum lines become brittle and may not fit tight on the connections-maybe you knocked one off. There's a few things for you to check-good luck.

Thanks for the welcome, 97Bird. The car was actually running as my friend's daily driver, and he claims there wasn't any problems to it. I had taken it to the gas station, had a full tank (but even trying to figure whats wrong with it really drinks a lot of fuel). The air filter is brand new; I had just replaced the wires, and I have platinum plugs installed, gapped correctly (from my Chiltons manual) at 0.45. I have checked all the vacuum lines--nothing. I did happen to change the fuel filter as well, but I still get the rough idle. The replacing of the fuel filter has noticeably changed the idling (doesn't die out as often, except at intersections), but I still have poor acceleration, and it idles rough at 1000rpms. I have yet to check it, but could it also be the air pressure in the fuel line? I dont know what the psi should be on the fuel injector line, but since I tinkered with the fuel system (changing out the fuel filter) and it made a difference, could it possibly be a low pressure which isnt sending a correct amount of fuel to the injectors?

I had an '87 2.3 LX. The timing belt skipped a tooth and produced exactly the same symptoms that you describe.
So, check the cam timing.