might be vacuum linkage, maybe low on trans fluid, computer
What engine do you have?
in the gas tank
you will have to have this evac by a a/c tech.
Not to be disrespectful, however you just answered your own question...if it's a V-6, there are 6 spark plugs!
Get under the car
180 km/h
I believe the 1988 Ford Thunderbird is OBD I , EEC IV ( there is probably an EEC TEST connection in the engine compartment )
1 A bent shifting fork from shifting hard 2 a worn bearing inside the transmission high miles or ran low of lube 3 a worn gear 4 hopefully an adjustment on the shifter
According to my Chilton's Auto Repair Manual : With engine oil filter change : The 1988 Ford Thunderbird engines ( 2.3 / 3.8 / 5.0 ) take : ( 5.0 U.S. quarts )
V6 firewall 3 - 6 2 - 5 1 - 4 front of Ford Thunderbird ----------------------------------- V8 firewall 4 - 8 3 - 7 2 - 6 1 - 5 front of Ford Thunderbird
that depends whats wrong with it and your mechanical skills
it has a timing belt