I had the most persistant hot starting problem when I first bought my wagon. Did everything that could break or wear out and never phased the problem. Turned out that the problem was caused by someone previously screwing with the air horn plate. They had gotten it off center and it was binding in the airhorn before returning to the zero position. This was causing more fuel to flow than the hot engine needed, but the cold engine started fine with the rich mixture.

The moral, check and make sure your air flow plate isn't binding in the air horn due to somebody previously futzing with it.

Just this week a fellow tech was trying to diagnose a hard hot start. Within 10 seconds I pointed out a 1.5mm gap on one side of the plate and a bind before coming back to the zero position.

Now would be a good time to mention this for anybody who may read it. Don't ever take the plate off of the arm, or even loosen the screw. There is no reason whatsoever to do this... ever.

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90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff