93 mustang check engine light on, does not shift properly

Ihave a 92 mustang will not shift 3-4 or od

The firing order and spark plug wiring layout is depicted in over-the-counter repair manuals like the Haynes for '87-93 Ford Mustangs. If you can't spend the ~$20 on one of those (available at Pep Boys, Autozone, eBay, Amazon, etc) you should be able to check one out from your local library.

That switch is in the trunk behind the plastic on the driver side by the taillights

I also have a '93 with a 2.3. I added Lucas transmission treatment (about 12 dollars) 2 years ago and it's still fine. However, it sounds like one of the clutches is worn.

run a code check then plug in the other safety switch

front clutch gone /failed or fluid level low .check with engine running handbrake on then put it in reverse and check level

Check the shift rods for binding, also check the hole ends, are the bushings bad? Hope this helps, let me know

have you checked the fuse box for blown fuses ?? hope this helps regards Jim

You have external linkage on there don't you? check that a shift rod has not fallen off and the shift gate is properly aligned.