The firing order for your 7.5 L ( 460 cubic inch ) V8 is :
1 - 5 - 4 - 2 - 6 - 3 - 7 - 8
The distributor rotor turns COUNTERCLOCKWISE
The engine cylinders are numbered :
firewall
4 - 8
3 - 7
2 - 6
1 - 5
front
On the front part
1-6-5-10-2-7-3-8-4-9
I'm not sure what it would be if it is a gas engine, but if its a diesel, its probably 1-5-3-6-2-4
The O2 sensor on a 1988 F250 is not near the engine. Go to the exhaust manifold and down the length. It is near the catalytic converter.
1-6-5-10-2-7-3-8-4-9
The order is 1.3.7.2.6.5.4.8. 1-4 front to back on the passenger's side, and 5-8 on the driver's side front to back.
The Ford 4.9 L straight six engine spark plug firing order is ( 1 - 5 - 3 - 6 - 2 - 4 ) The distributor rotor turns CLOCKWISE
F250 FIRING ORDER 6 CYLINDER 1... 5... 3...6 ...2 ...4.
Distributor rotates counterclockwise. Firing order: 1-5-4-2-6-3-7-8
For a Ford 4.9 liter / 300 cubic inch inline six cylinder engine : The firing order is ( 1 - 5 - 3 - 6 - 2 - 4 ) The distributor rotor turns CLOCKWISE The marked # 1 position on the distributor cap faces AWAY from the engine The engine cylinders are numbered 1 to 6 , from front to rear
1-3-7-2-6-5-4-8
Answer1,3,7,2,6,5,4,8 is the firing order. The cylinders are numbered 1-4 from front to rear on the passenger's side and 5-8 from front to rear on the driver's side. THIS IS WRONG. THE CORRECT ORDER IS 1,5,4,2,6,3,7,8, COUNTERCLOCKWISE ROTATION. FIRING ORDER IS ALSO LOCATED ON THE INTAKE MANIFOLD, AT LEAST IT IS ON MY 97 F250 HD 7.5, THE OIL COMPANIES JUST LOVE US.