1990 Toyota Corolla Engine Backfires & Shut off

Could be either fuel presure or ignition, clogged CAT.

Fuel pressure check on the 4AFE requires a special tool set, since there is no test port (you remove the cold start valve fuel supply and screw in a special adapter).

Timing belt should be changed every 60K.

Check condition of cap, rotor and wires, have fuel pressure checked and inspect timing belt condition.

Thanks for answering so fast. timing belt is almost new (100 miles) so I am going to check fuel pressure, D.cap,rotor and wires first, and besides of the new condition of the timing belt I am going to look at it. I guess when you guys talk about clogged CAT,it means clogged exault pipe?... Excelent job you do here, Bob,Ken & all the team !!! Best Regards.

Manuel Perez

A clogged CAT is the convertor. Convertor is first in exhaust stream after O2 sensor and is bolted in place, you can remove bolts and visually check the CAT, look for melted material, or cracks. If you do this, you will most likely need new bolts and gaskets.

If CAT is bad, you need to find cause, which is usually a rich mixture caused by failed sensor. If your check engine light is on, short TE1 and E1 terminals of the diagnostic terminal, turn engine to "on" (do not start) and check engine light will flash codes, for example, flash..pause..flash,flash is code 12, each code will flash three times.

As I mentioned, you need a special tool set to check fuel pressure, you remove cold start valve fuel supply from rail, screw in special fitting, then use mechanical gauge to check fuel pressure.

Ok, I got it. there is no check engine light on. in fact I did TE1 & E1 terminals test and it was Ok.(1flash, pause,1 flash) I am going to check CAT like you tell me. Will try to find help in the fuel pressure test, check timing belt & timing,D cap,rotor & wires.
I hope I can find the fault, as soon It happens,I let you now. Thanks one more time. See you guys later.

Manuel Perez