DC2Mex

I have a gsr turbo that was tuned about 4 months ago and was running perfect until the past month. it started at first at high rpm it would sound like ignition was breaking up. Also on a cold start the afr would be lean out to about 15.7 and will stay there even when car was warmed up. if I would then drive it for ten minutes or so and shut it off and started it back up afr ratio will be at 14.7 and will stay there. It sputters on idle constanly and while driving too. If I would give it some gas and let off it would start backfiring. it wasn’t doing it right after I got the tune and it would keep getting worse. So I changed out spark plugs and gapped to .19 but didn’t help. Now the car sounds like its misfiring really bad. It almost sounds like a Harley. Afr is now at idle is at above 16. And sometimes jumps from 13 to 17 and all over the place. Its sputtering and choking while driving at any rpm as well. I changed out the spark plugs and distributor and didn’t help anything. Next I plan on changing out the fuel filter. Anybody have an idea on what it might be or guide on the right direction on diagnosing this problem would be greatly appreciated. Thanks
Forgot to mention it’s a 98 gsr with stock ignition ngk wires and bkr7e’s gapped to .19. For fuel im on 91 pump gas with id 1000s with walbro 255. Car made 440hp on s300 tuned at church automotive.

motoxxxman

check fuel pressure when everything is nice and cold and has been sitting for a while, check it with engine not running by just cycling the ignition. then check it again with the engine running. then pull the vacuum line off the fpr while it's still running and cover the hose with your finger to plug it and see what pressure is then. also look at what your afr does while the hose is removed from the fpr.

might have clogged filter, might have a clogged pump strainer.

also, you said you replaced the distributor. did you set the base ignition timing properly after installing it?
have you done a valve lash adjustment recently? compression test? any trouble codes stored?

Digmaster

I would go over the fuel system sound like some might be clogged start with the simple stuff fuel filter and just work your way back. Do you have a fuel pressure gauge what's it reading at idle and wot??

wantboost

iTrader: (2)

yea it definitely sounds like a fuel supply issue to me

as others have stated

check the sock filter on the intank pump and make sure it isn't clogged with who knows what
check/change/replace the fuel filter.
Pull the fuel rail off, leaving the injectors in and wired up and have someone crank the car so you can see if all 4 injectors are firing as they should and aren't clogged. If the injectors show a weak fuel stream, poor spray pattern then take them out of the rail and check the inlets for debris, sometimes they'll have screens on the inlets similar to OEM injectors

Install a fuel pressure gauge on the rail and get a gauge for inside the car. this will let you see exactly what the fuel system is doing all the time. or you could hook up a digital pressure sensor and wire it to your ems to datalog fuel pressure

DC2Mex

ok I am going to go over the fuel system and see if anything is clogged. i just checked my stock injectors and there is a small screen on the inlets. Do ID 1000's come with there own screen or did i forget to put them on? I didn't have access to a timing light to set base timing but i would imagine i would be able to feel a difference if it was the distributer that was bad. i hoping its just a minor problem.