1989 Suzuki Sidekick engine wont start

Could be the fuel pressure regulator/injector sticking /fuel return line clogged-up

Thanks, i tried all of that and still to much fuel so i ended up taking it to my local shop and the replaced the ecu and that got it going however now the engine stutters under light load around 2000 - 2500 rpm while driving so i replaced the cap rotor wire set and new plug and new fuel filter. i also checked the compression and have 150psi across all cylinders. i have talked to a couple of people and they think that the used ecu is no good. just looking for some more opinions