just did a tune up on my 1990 Cadillac brougham and had the same issue, causei was a meathead an didnt mark number one on the distributor. number one is to the immediate left of the ignition coil wires, if you have the coil in cap kind. and the firing order is 1-8-4-3-6-5-7-2, and if you have an olds 307 V8 engine it goes counter clockwise around the distributor cap, it is different for the other engines, and of course v-6's. good luck
the firing order is from left to right 1234 then the order is 1324 or 1423
firing order is 1, 3, 4, 2 for a 86' B2000
18436572
1,3,4,2.
1342
1-3-4-2
The 5.0L 305 V8
Standard firing order for almost all v8's 1-8-4-3-6-5-7-2.
1, 3, 4, 2. Clockwise.
165432 distributor rotation is clockwise
Be sure the firing order is correct, you may have two wires crossed. The firing order is 1, 8, 4, 3, 6, 5, 7, 2.
1-8-4-3-6-5-7-2