From what i'm told when the CEL flashes it means its backfiring, (please correct me if i'm wrong) So my question is (assuming the part about the backfiring is correct) then what causes it and how do i fix it, and is there any trouble shooting I should do?

P.S.
Have any of you found the CEL codes with a test light as opposed to an OBD1 meter, if so do tell, as the diagrams i found have a port that i don't have on my 89 four banger?

Thanks guys :)

 

I know my truck has backfired once or twice, but i've never had a flashing CEL, and i run OBD1, but normally back firing is due to spark/coilpack issue

 

Flashing cel means there is a very high risk of the cat conv being damaged. This could mean your running to lean (not enough fuel to much air) or rich (to much fuel not enough air) both could kill your cat conv and your ecu wants you to know that. It's odd the engine runs normally when the cel flashed though because normally by the time the cel starts flashing the engine is already running rough backfiring ect.

 

yeah see both coil packs are firing, soo thats what i don't get, and the truck only ran rough one time, which was yesterday morning, i went away for a week, drove fine sunday, went to school on monday, i started it, let it idle since its cold, then right before i went to pull out the RPM droped and acted like it wa going to stall, then acted like it was going to do it at the bottom of my driveway, then pulled out, shifted, CEL turned off when i took my foot off the gas, the kicked when i reapplied gas, and CEL accompanied the gas, went like that way the whole way into school until i got into town, no rough riding or CEL after that until this morning when i got to school it came on, so i'm gonna got to Advanced Auto Parts and borrow a scanner, and see what comes up, the backfiring into the intake is just something i heard about and wanted to investigate it.

btw, i don't have to worry about a catyletic converter, but what would be causing the lean mixture and reading up on backfiring manifold back firing is from being to lean and exaust backfiring is from being too rich.