I got the same hesitation problem, but also the car is very hard to start to now.
It seams to be hard to start almost all the time, and also stumbles on acceleration except for really slow acceleration.
Can kill the engine when I really step on the gas (fuel pressure spikes to about 42psi when I open the throttle)
Could it just be bad gas?
bad oxygen sensor saying car in open loop at start?
IAT (intake air temperature sensor) bad, any specs to check this out?
bad computer? (floor wet after rain, on computer side)
What I have checked so far.
1. Spark good, distributor cap looks worn though
*was running fine, then had problem, then ran fine again so shouldn't be from cap.
2. Compression ~152psi all cyl.
3. Fuel 32psi idle and no vacuum line connected ~40-42psi idle
4. Checked signal to injectors when cranking with no start, Working
5. Checked Main Relay, all power going out.
*voltage a bit low to fuel pump but fuel pressure good. (could it be dropping power to computer / ecu on start?
6. Ignition Timing was recently adjusted, after first time car stumbled on acceleration.
7. Checked TPS was .3 to 4.3 volts when measured from computer pin to battery ground was smooth all the way though.
8. Spark plugs where worn to .052 inch re-gaped to .040 inch
9. Spark plug Wire resistance was 6,900 ohm - 8,900 ohm for the longest wire
Any other things I should check?