my 90 rx won't start when it is hot and idle is all messed up. the only mods are header, glass pack, 3 1/2 tips the intake manifold was taken off and the welds were grinded and the smog pump was taken off and the sleves were removed. i made some block off's for were the smog pump and actuators bolt on any ideas

Is it throwing any ECU codes?

This could be just about anything. .. .

no just one for the O2 that is about it

How many miles are on the engine? There are a few things it might be. Worst case scenerio would be low compression.

Hi,

yes I agree that this may be due to low compression. Pls. check the mileage meter.

Another vote for low compression here!!

Rebuild time by the sound of it