Remove the spark plugs and slowly rotate the engine by hand until you feel the piston coming up on the compression stoke. You can place your thumb over the plug hole and you will feel the compression stoke. Once you feel it, place a long screwdriver in the plug hole and watch as it slowly rises. Once it gets to the very top, you are at TDC. You must go slow and do not get the screwdriver stuck. If you cannot use a screwdriver click the link.
On the engine shroud above the spark plug
The spark plug gap for a 1988 Ford Mustang is: .044" for the 2.3L 4-cylinder engine .054" for the 5.0L V8 engine
Put the IROC up on jack stands and remove the spark plugs from under the engine.
0.035" gap
According to one of the Ford websites : For a 1988 Ford Escort , 1.9 litre four cylinder engine : The spark plugs are gapped at ( .044 inch )
In a 1988 Ford E-150 : If you have the 4.9 liter / 300 cubic inch inline six cylinder engine , you need ( 6 spark plugs ) If you have the 5.0 liter / 302 cubic inch V8 engine or the 5.8 liter / 351 cubic inch V8 engine , you need ( 8 spark plugs )
According to one of the Ford websites : For a 1988 Mercury Cougar , 3.8 liter V6 engine : ( the spark plugs are gapped at .054 inch )
Your local autozone can tell you. If they can't ask for spark plus for a 1988 Ford Thunderbird with a 5.0 engine.
According to one of Fords websites : For the 3.8 liter V6 engine in a 1988 Mercury Cougar : ( the spark plugs are gapped at .054 inch )
You fail mention which engine. Look at the link to the right and choose the correct engine.
.044 inch ( for the 460 in a 1988 Ford truck , according to www . motorcraft . com - no spaces )
According to one of Fords websites : For a 1988 LTD Crown Victoria : 5.0 liter / 302 cubic inch V8 engine ( the spark plugs are gapped at .050 inch ) 5.8 liter / 351 cubic inch V8 engine ( the spark plugs are gapped at .044 inch )