My buddy just bought a civic si that didnt run when he got it. But as we messed with it a bit we got it to start. now it runs fin at idle but when i give it gas suddenly, it will stall. but if i apply the gas very slowly, it will rev up. also it will start right up sometimes, and sumtimes it will crank and crank and crank before it starts.

Already changed plugs, cleaned contacts inside distributor checked vacuum lines. also there are no CEL or codes from ecu

 

have you tried checking the main relay?

 

No I haven't. How do I check it?

 

look in the FAQ, theres a thread about testing relays,if its good turn your ignition ON and listen for the fuel pump to prime(sounds like a phone on vibrate )if it doesnt prime, replace


become familiar with FAQ and SEARCH; great source of info