I have a 92 Tempo with a 2.3. The car was parked for several years and has 77,000 original miles. I bought it cheap because of how poorly it ran.

Initially it missed really bad and could barely get up to speed. I replaced the plugs, wires, cap, rotor and coil. This improved it dramatically but did not solve. I removed the idle control valve, cleaned it and made sure it worked. I also removed and cleaned the throttle body. These also improved things. Now I am stuck.

Starting is rough and takes a few tries. At idle there is a slight misfire. As I drive, it does fairly well under slow acceleration but the shift patterns are off. Sometimes it shifts normally, but others it won't. For example, sometimes it won't shift out of first until close to 30. Other times it shifts down very abruptly when slowing down.

On the highway it does fine if I accelerate gradually up to 60 and runs good at 60. Try to accelerate past 60 and it sputters and has a slight misfire.

I'm looking for suggestions here. Thanks.

 

You did not mention anything relating to fuel. If the fuel was in there for several years a lot of things could have become gummed up.
If you already did the following, just disregard the suggestions.
Fill the tank with a load of fresh gasoline, then add some injector cleaner and make sure to change the fuel filter. Also a thorough check for any leaking /cracked vacuum hoses is always a good move. Without knowing it's past, if it ran good when parked, big if, than many times performance might improve through use.
The condition of the trans fluid can tell you if there was a previous problem.

 

Great info hanky !!

 

I have gained a lot of ground since my initial post. I watched a trouble shooting video on something related to some of the issue and it prompted me to pull the EGR valve. It was stuck open so I replaced it. EGR valves that are stuck open create or resemble a vacuum leak.

That improved things dramatically. The symptoms that remain indicate a vacuum leak. It's just a pain to track down. What it still does...

It starts somewhat hard when the engine is cold, but idles almost normal. Very little surging. Once reaching normal operating temps, it idles somewhat rough and revving causes some backfire. It hesitates and sputters under hard acceleration, but nothing like before. Getting up to highway speed is easy now but it will still sputter under acceleration past 60-62 MPH.

The shift points have improved but still act up occasionally. The transmission fluid level is full and the fluid looks normal and doesn't have an unusual smell.

I do plan to change the fuel filter for good measure, but the remaining issues I believe are vacuum related.