speedometer and cruise don't work

I had the spark plugs, spark plug wires, valve gasket replaced. Still having a problem. There was oil all over spark plug boots because of valve gasket leak, put new spark plugs in before leak was fixed but my mechanic fixed the gasket and wires and didn't replace spark plugs because they were new. Still having a problem. I can start up a hill fine but at a certain point it just bogs down and won't accelerated, i have to take my foot on and off the gas to get the car going again. Same thing when I am driving at 65 mph. It will be fine then suddenly drop speed. Should I just replace the spark plugs again? I don't think that is the issue. Also the check engine light comes on when it happens and then turns off. Otherwise the car runs very well it only has 160k miles on it. I have had it for 6 years. Also I had this problem a while back then it stopped after cleaning a small piece of foam in the air filter system. I don't think that's what stopped it because I did that again and it didn't change this time. It actually started again when I had the struts replaced and got a regular oil change. I let a broken strut spring go for a long time so the rear end of the car was sitting low for a long time and now it sits up right. Don't know if that makes a difference but thought I would give all details.

air and heat blower>???

temp gauge went to hot& back to normal ,car shut of while driving. turned over but would not start.pulled plug wire & found oil halfway up two plugs. what would cause this?

Found oil halfway up plug when i was going to pull one out. iwhat. would cause this?

today i put the old one in and the car didnt stall but check engine light came on with the new mass air sensor
the check engine was off what would the car to run rough

f6rz9c915da is the ford part number and it has been discountued. Must be another part that will work from a diferent model.

The AC quit at the same time.

I put it in gear and push on gas it asks like there is a lot of rain,snow or ice. Had it checked out, person said it was traction sensor.

I'm looking for part S3206 with the greatest reliability.

started 1 week ago

Looking for the r and r of a starter on a 1996 2.0 Mystique