89 camry hesitates to accelerate

hi, for last 9 months, my 89 camry has been playing up in the first 5-10 minutes of driving each day. used to stall (and engine check light will appear) and wouldn't start for bout 20mins, but this hasn't happened since new idle speed motor installed 5 months ago. since then car will hesitate to accelerate, eg. have to hold accelerator down for a couple of seconds for reaction. will happen 2-7 times in a row, after 10-12 mins of driving it will be ok, happens bout 2 out of 3 days and more likely when cold and/or wet. only happens at low speed and longer hesitation occurs when car is still, eg. taking off from green light. intermittent problems have been mentioned, but mechanic can not track down pin point source. thanx

What engine/transmission?

SV21, auto

3SFE?

not sure what that is. it is cs model, 2L, fuel-injection if this helps.

See if the ECU is giving any codes.

yeah, i had a new computer installed before the idle speed motor, this was thought to be the initial problem, but i guess not

Since you had a new ECU installed, I would check the timing.

Make sure it's set to 10 degrees BTDC.

Sounds to me that the ECU is not accepting the readings.

Are you also experiencing rough idle?
If yes, perhaps you're also experiencing a misfire as well....

timing belt replaced not too long ago

idles just below 1000
when starting though it idles at 1600 in park with hand break on. is this too high, im not sure. other than that, idleing is consistent

Sounds like it's running in a default mode until something kicks in. Check the oxygen sensor(s).

RPM by default should be 750RPM after the car warms up.

During the warm up period, it can range between 1000-1600 RPM, but eventually, it comes down to 750RPM...

with the 4 cyl versions of this car u need to check the disstibutor and coil conections, if thats not it then check out the line going to the distributor it is a vac line if oil gets into this line witch it happens alot, that is more than likely the issue