I just swapped motors in my 99 GC, putting in a 4.0 from a 2000 GC. I get a Check Engine Light that's solid until everything is warmed up, then as soon as I come to an idling stop the CEL begins to flash. I've swapped out the ignition coil, checked the gap on all of the new spark plugs, replaced the gas cap, even Seafoamed it. I still get the CEL. It seems to run fine when underway but the idle is a little rough. Any ideas?

 

take it to autozone/oreillys/napa/any other auto parts store and ask them to scan it.

 

Flashing CEL means something is wrong with the Catalytic converter OR O2 sensors, if I remember correctly. Someone please verify/correct.

 

Step one is to find out what the code is.

 

i always thought flashing check engine light meant something imperative to the operation of the vehicle was going wrong

 

A flashing check engine light usually means unburned fuel is getting into the catalytic converter and burning there which will kill the cat in a matter of no time. Once you smell rotten eggs it too late.

 

Yeah, a flashing cel means "shut it down now" in order to save the catalyst.

 

My code scanner gives me 0301, cylinder #1 misfire, but I've changed the coil and the plugs. What else?

 

Injector?

 

Injector

 

Injector.(s)

 

Take out the plug and make sure it's clean and gapped correctly.

 

He did