Vehicle cant start fuel supply ok ingnition ok engine comprassion is ok

I believe that they are interchangeable up until 1997.

Your timing belt may have stretched and jump timing,take cover off to inspect belt,here's a link on how to do. How to Change the Timing Belt Water Pump1990 1994 Lexus LS400

Now, I'm not saying this is a fact, but my TH700R4 trans did that very thing, wouldn't come out of third. And with no 3rd it won't go to overdrive. I rebuilt the trans and found the overdrive drum was all scarred and caused the limp home thing to happen, third gear was as high as it would go. I suggest you have the trans checked out by a professional trans shop. As for it being a bear to start, that's a faulty temperature sensor. If it's not functioning, the computer doesn't know to put it into cold start mode, which increases the throttle speed and puts more fuel in the engine for starting when cold. Like a automatic choke system in earlier vehicles.

Since work was recently done to the vehicle I would look to see if any connections were left unplugged or inadvertantly knocked loose. Make sure to check the battery terminals and cables to ensure tightness and a solid connection.

ck relay to fuel pump bad

Check the ignition switch, there is battery voltage to the fuel pump and ignition, because the engine starts with switch in the start position, now check the above with the switch in the run position, If there is no voltage replace the switch.

I HAD THE SAME PROBLEM WITH MY CAR. 93 LS 400. THAT WOULD BE YOUR FUEL FILTER OR THE FUEL PUMP GOING BAD. TRY CHANGING THE FILTER FIRST. THE DEALER TRIED TO CHARGE ME $980 TO CHANGE FUEL PUMP.

Had same problem on 93 LS400, timing was off one tooth on left camshaft gear. Replaced belt and reset and no more problems. (Spent 1200.00 on repairs I did'nt need)

ok, i tell you 3 possible causes.
check maf sensor connection , check fuel pressure regulator (max press fuel in rail 40 psi) , check engine compression (min 95 psi ) if less this cause spark plugs wet and not start