my 91 929 with i'm told a 92 engine, won't pass echeck, getting excess nitrous oxcide readings, chugs on highway exit/on ramps, would a new fuel filter help?? thx for any input.

It might help. I would check the pickup in the distributor. Put a volt meter across the two wires you should have 6volt. I changed my distributor and had to run new wires to the computer which requires shielded cable. Mine would run perfect and then loose power and shake then run perfect. Normally a rebuilt distributor from nopi will cure it.