Crankshaft position sensor (CPS) problem. Maybe
 

Hello

I have a 1998 Nissan Sentra GLE 1.6L 5 speed manual. Above say 4,000 RPM there is what I can only describe as a severe misfire. This happens in all gears, stationary or moving, going up hill or coming down. It's purely RPM driven. From that I've concluded that it's not related to fuel although I have put in a can of Sea Foam to see if that helps. From reading around the Web, the crankshaft position sensor appears to be a primary suspect. Plus I did get a warning from my OBD2 connected smart app was about to fail.

Anyways, I've replaced the CPS which being located at the front off the car attached to the bell housing is a 15 minute job. No change.

So does anyone have any other ideas
The CEL is off and there are no stored codes

Any help would be much appreciated
Thanks
Barry