I've been having a lot of problems with my motor.

When I start up from cold, it's fine. Good idle and revs smooth.

When I take it out for a test drive, after a few minutes, I notice it starts to hesitate when I press the gas.

It gets worse and worse, so that after a couple more minutes, the car won't drive. I can't press the gas without the car popping, misfiring and stalling. Then it just won't start.

It seems like fuel starvation to me, but the pump is new.
I've tried new injectors, iacv, inlet temp sensor, lambda.

No cel.

Any ideas?

 

Are you saying the car is overheating? What mods have been done to the car? Are you getting any CELs? Last tune up? Check timing?

 

The car gets up to operating temp, not overheating.

No major Mods - alloy fuel tank.
Walbro 225 LPH external fuel pump.
Aem fuel pressure regulator.
4-1 manifold
Stainless exhaust - no cat
Lightweight flywheel.

No cel.

Not touched mechanical timing, but set ignition timing. New fluids, filters, plugs, distributor, leads.

 

This happens since when? Why haven't you verified the mechanical timing?

 

When the engine is warmed up and running poorly, unplug the primary O2 sensor to see whether the problem is eliminated.

 

I am having the same problem in my crx b16a2. I unplugged. the primary o2 sensor and it still didn't work. When it was cold it will idle at 1000 rpm but when it hits 150 on the temp guage it revs up to 1.2 rpm, revs higher then dies down like its about to run out of gas and the idles back up to 1.2 rpm. I've tried the fuel injectors, fuel pump, all the plug sensors on the throttle body.

 

Did you do anything new to the engine prior to it running bad?