Four
.144
According to one of Fords websites : For a 1989 Ford Thunderbird , 3.8 liter V6 engine : The spark plugs are gapped at ( .054 inch )
.044 inch
The first thing to do if one cylinder is not firing on a 1989 Honda Civic SI, is to disconnect the battery. Then remove the spark plug wire and the spark plug. Check to see that there is no oil on the plug and it has the right gap measurement. Then replace the spark plug and wire and try the engine again. If it is still misfiring, change the spark plug. If that does not fix the problem, have a compression check done for that cylinder.
According to one of Fords websites : For the 2.3 liter four cylinder engine in a 1989 Ford Tempo : ( the spark plugs are gapped at .054 inch )
According to one of Fords websites : For a 1989 Ford Escort , 1.9 liter four cylinder engine : The spark plugs are gapped at ( .044 inch )
0.060 inches
There is a CEL, Check Engine Light, on the 1989 Thunderbird.
According to one of the Ford websites , for a 1989 Ford Festiva , 1.3 liter / 81 cubic inch four cylinder engine : ( the spark plug gap is .044 inch )
.044 inch , according to my Chilton book and ford parts . com
.044 inch ( according to motorcraft.com , one of Fords websites )