I'm trying to retrieve any codes on my 91 4R 3.0 in the quest to fix my smog troubles(high hydrocarbons).I followed the manual:warm engine,neutral,accessories off,jumpered wires on diagnostic plug.When I turn the key to on,the check engine light just flashes non-stop with no delays.The check engine light was not on when driving it but I just wanted to see if anything was there.According to the manual,it should flash one time every few seconds to indicate there are no codes.Please help.

On my '85 & '89 Supras, quick blinking CE light meant no codes stored. I wouldn't sweat it.

My neigbor had a Celica that was failing emissions for high HC, and the fix ended up being a new thermostat, his was stuck partially open, and never allowed the engine to warm up properly. If yours has never been changed, do it, and use OEM parts, maybe a new thermostat/gasket and radiator cap.

I think the thermostat may be a PIA to change on the runner, it's actually in the front middle of the engine instead of on top, like most I've seen, this according to a toy mechanic.

Thanks for the info.Luckily,I did a retest on the smog and passed with flying colors just by doing simple tune-up stuff and going back to NGK plugs.The results are under my "smog retest:amazing!" post if you're interested.