Wasn't the CPS.......

Having start problems, as in will turn over but won't fire up.

When it died it ran rough for awhile, was warming it up in the garage and it started choking/coughing, some light backfiring, then died. I could get it started again, but would still run very rough. That lasted for a bit, now it will just turn over, but not fire up.

I figured in was the CPS, changed it (you know how much fun that little *** is to reach) and .....no go. Now I have a CPS for the spare box.

What's next? Checked for spark already. Could it still be the coil, low/weak spark? TPS? Fuel pump or related? MAP? Any suggestion would be greatly appreciated.

TIA

Since you say you have spark, eliminate the next most obvious thing, fuel pressure. A simple test is to turn on the key, listen for the pump to quit running. Turn it back off, wait a few minutes and then press in the center of the schrader valve on the fuel rail. You should still have pressure. That doesn't prove the pump is good but can be a quick indicator of one failure mode on a fuel pump.

There tends to be only a few sensors that can cause a no start situation. First is the CPS, second is the MAP, and third is the camshaft position sensor in the distributor. The camshaft sensor will normally prevent any spark at all. I have also seen a ballast resistor on the fuel pump cause problems when it doesn't fail totally open but the resistance goes up 2x. You can check that one quick by jumpering around the resistor for testing or limited use.