WHY IS MY 302 CID RUNNING, WHILE IT IS WIRED IN THE 351 FIRING ORDER?

2 possible reasons 1 check ignition timing and adjust. 2 check for crossed plug leads on 2 cylinders --firing order.

Yes the ECU should not affect the systems different firing order. If you want the correct ECU go here to purchase one.

255 cid (4.2L), 302 cid (5.0L), 360 cid (5.9L), 390 cid (6.5L), 460 cid (7.5L) V8 engines Firing order: 1-5-4-2-6-3-7-8 Distributor rotation: Counterclockwise




351 cid W & M (5.8L), 400 (6.6L) engines Firing order: 1-3-7-2-6-5-4-8 Distributor rotation: Counterclockwise

FIRING ORDERS NOTE: To avoid confusion, remove and tag the spark plug wires one at a time, for replacement. If a distributor is not keyed for installation with only one orientation, it could have been removed previously and rewired. The resultant wiring would hold the correct firing order, but could change the relative placement of the plug towers in relation to the engine. For this reason it is imperative that you label all wires before disconnecting any of them. Also, before removal, compare the current wiring with the accompanying illustrations. If the current wiring does not match, make notes in your book to reflect how your engine is wired. Fig. 1: 300 cid (4.9L) inline six-cylinder engines Firing order: 1-5-3-6-2-4 Distributor rotation: Clockwise
Fig. 2: 232 cid (3.8L) V6 engine Firing order: 1-4-2-5-3-6 Distributor rotation: Counterclockwise
Fig. 3: 255 cid (4.2L), 302 cid (5.0L), 360 cid (5.9L), 390 cid (6.5L), 460 cid (7.5L) V8 engines Firing order: 1-5-4-2-6-3-7-8 Distributor rotation: Counterclockwise
Fig. 4: 351 cid W & M (5.8L), 400 (6.6L) engines Firing order: 1-3-7-2-6-5-4-8 Distributor rotation: Counterclockwise
Fig. 5: 6.9L diesel engines Firing order: 1-2-7-3-4-5-6-8

FIRING ORDERS NOTE: To avoid confusion, remove and tag the spark plug wires one at a time, for replacement. If a distributor is not keyed for installation with only one orientation, it could have been removed previously and rewired. The resultant wiring would hold the correct firing order, but could change the relative placement of the plug towers in relation to the engine. For this reason it is imperative that you label all wires before disconnecting any of them. Also, before removal, compare the current wiring with the accompanying illustrations. If the current wiring does not match, make notes in your book to reflect how your engine is wired. Fig. 1: 300 cid (4.9L) inline six-cylinder engines Firing order: 1-5-3-6-2-4 Distributor rotation: Clockwise
Fig. 2: 232 cid (3.8L) V6 engine Firing order: 1-4-2-5-3-6 Distributor rotation: Counterclockwise
Fig. 3: 255 cid (4.2L), 302 cid (5.0L), 360 cid (5.9L), 390 cid (6.5L), 460 cid (7.5L) V8 engines Firing order: 1-5-4-2-6-3-7-8 Distributor rotation: Counterclockwise
Fig. 4: 351 cid W & M (5.8L), 400 (6.6L) engines Firing order: 1-3-7-2-6-5-4-8 Distributor rotation: Counterclockwise
Fig. 5: 6.9L diesel engines Firing order: 1-2-7-3-4-5-6-8

1995 and later 302 firing order is 1-3-7-2-6-5-4-8

My 1991 302 likes to run at 12 degrees Before Top Dead Center.

Need to know the engine size. You have these choices:
4.2 L Essex V6
4.9 L inline-6
302 CID Windsor V8
351 CID Windsor V8
4.6 L Triton V8
5.4 L Triton V8
6.8 L Triton V10
7.3 L Power Stroke V8
6.0 L Power stroke V8
TD

The firing order is 1-3-7-2-6-5-4-8.

This is from compcams website:

Firing Order, Small Block & SVO
This is one of the most common questions asked by our Ford customers. The firing order for the early 221-302 engines and the early 5.0 engines is 1-5-4-2-6-3-7-8. This is the firing order for all prefix “31” cams and is the standard replacement cam for all early engines. The later 5.0 engine and all 351 engines are designed to use the 1-3-7-2-6-5-4-8 firing order. This is the firing order for all prefix “35” cams, and cams ordered for these engines should use this prefix. Other than the firing order, the cams are identical. By changing the spark plug wiring at the distributor these cams can be interchanged.

I hope that this helps.

Tim