92' Camry Starting Problem

'92 Camry 5S-FE 4cyl 2.2L A/T; This one has me puzzled. Runs well, newer ignition parts, but does not start when warmed up to OpTemp. Starts fine cold, restarts when warm after 5-10 minute cool down (is not overheating). Will start hot if starting fluid is injected into throttle body, so problem is unlikely spark, it has to be fuel, right? Just ran SeaFoam thru top end as I was advised it could have been carbon build up, but that did not fix. Got some carbon burn off, but hot start issue remained.

Could it be fuel pressure regulator? Fuel pump and filter both replaced less than a year ago.

Any ideas or pointers would be greatly appreciated, I have basic tools, but not much more than a Multimeter for test equipment. Thanks, and we love the brothers at my house, they make my Saturday mornings so enjoyable.

The problem might be with the Main Fuel Injection relay. This is located in the underhood fuse/relay box. So underhood temperatures might be effecting the MFI relay where it doesn’t work when hot.

Tester