2000 Jeep Cherokee 2wd, 4.ol engine. No fire on number 2 cylinder, code set for number 1 and 2. Po351 and p0352, had another could rail from a 2001 and its doing the exact same thing. Hard to believe that two rails have the exact same problem? Back story, bought 2000 model wrecked, front fender and front axle brackets bent. Bought 2001 as parts donor, replaced fender, airbags, axle,etc. Airbag light not on, everything works as should. Rebuilt engine, new pistons, cam, etc. Fired right up but had rough idle, got worse, now missing on number 2 cyl.. any thoughts, crank sensor?

 

That is a waste spark engine in which 2 plugs fire every revolution. One on compression and one on exhaust. They pair up as 1&6 fire together, 5&2 fire together, and 3&4 fire together. Each pair fire on a separate coil in the rail, so the problem isn't in the rail or the wiring. I would suspect the injector circuits. Check the injector plugs for chafed or shorted wires or broken strands. All the injectors are wired hot and the computer grounds them thru drivers when needed to supply fuel. It controls injector on-time to control mixture and uses the cam sensor for timing.

 

Also run a compression test on nbr 2 also grab the injector between 2 fingers with the engine running...you should feel a definite click click click as it physically opens and closes

 

I would agree look at the injector wiring and maybe the injector . you can use the screw driver trick to hear the injectors work .

 

Thanks for all the input. I grounded all 6 plugs and did a fire test. # 2 had no spark. Replaced coil rail with new one and fixed the issue. Hard to believe two rails had the exact same problem but they did.

 

wow good catch