How do i adjust fuel/air mixture?

A few weeks ago, my 95 eclipse gs started shuddering under load in the low rpm range, and got steadily worse over the next weeks. last weekend i got sick of it and took out the plugs. the electrodes were really really white, which i assume means i was running to hot/lean. so i replaced the plugs, and it ran great for a day or two, and now i'm starting to feel the shudder come back a little, which i'm sure will get worse over the next few days. how do i fix this? is there some way to adjust the fuel/air ratio? any help whatsoever is appreciated.
-j

Rather than adjust the AFR, figure out what shit the bed and caused the change in the first place. On that car I wouldnt know where to start. Being to lean is usually a problem at high rpm, not low rpm. Are there any CELs?

what's a cel?
and what might have shit the bed?
i dont know what else to look for that might have gone bad
thanks

CEL = Check Engine Light

DTC = Diagnostic Trouble Code

nope, no check engine lights, sorry

could be your o2 sensor ig going slightly bad, but not enough to trip a CEL... or fuel pump is gettign shitty...

how would i investigate a faulty o2 sensor? some sort of obd2 diagnostic software or something? is that expensive? and what about the fuel pump? how can i tell if it has shit the bed?
thanks

95gs isnt obd-II compatible.

shit.
well does anybody know how to tell if a fuel pump is bad, or how to test an 02 sensor?

crap, im not sure, but someone on here should know, just give it a few someone will help you im sure. Do a google search for testing fuel pump, or 02 sensor, try to find one for a 2g

If it was a fuel delivery problem it would get worse at high rpm.

To check the O2 sensor connect a scan tool or datalogger and watch the trace. If there is no CEL theres no help reading the codes. You could just replace it, but that costs money.

I'm still not convinced this is a fueling issue.

yeah that's what my dad says, if it was a fuel problem it would get worse at high rpm....... but at the same time, why did it go away when i replaced my plugs? weird, right? btw, thanks a lot for all your help, af is great :)

hmmmm... possibly plug wires?

ok, i guess i'll look into plug wires/o2 sensor/fuel pump, and see if any of them are faulty if i can..... where do you suggest looking for these things besides ebay?

and hey, does anybody know how to monitor fuel pressure on my stock 95GS? Or how to monitor the o2 sensor? because if i could find where the problem originated, it would probably save a lot of diagnosis time....