I have a 96 hatch with a gsr swap s300 ecu. the other day it shut off on me when taking off from a stop sign. I pulled over i revved the engine and when it hits 2.5k it drops down by itself then it goes back up hits 3.5k then it drops again then itll go all the way up. This all happens while i maintain the gas pedal down. No CEL at all, I took off the iacv and cleaned it, it was pretty dirty but it hasnt fixed the issue. While im driving if i give it more gas it feels as if theres a delay then it bucks and then itll go. This causes issues when trying to take off from a light cause itll shut off or when shifting because when i give it gas it bucks after about a half a second delay. Anybody deal with this issue before? Any input is appreciated

 

Inspect the plugs, wires and distributor. Also check the ignition timing.

 

Skipped timing belt. I've had one fail during a very routine drive off from a stop. Seems to be a high stress on the belt at that time.

 

I have a 98 civic (automatic) that has similar issues. Almost wants to stall every once in a while when I'm pulling out of a parking spot in low gear. It seems to be random, but it usually does it when the engine is cold. My car is also pretty jolty when I give it gas and it changes gears at low speed.

I used an OBDII scanner and i have a bad barometric pressure sensor, I'm going to try replacing that and see what good it does.

I was told that if that doesn't work to check the spark plugs and distributor.

 

You need to replace the ECU.
And make your own thread rather than threadjack the OP.

 

may need a fuel filter or new fuel pump.