I have a 94 z28 6 speed, I seem to be having a problem with the car loading up really bad on fuel...

Black smoke when you are 'casual' driving and lots when you get on it. The car pretty much falls on its face when you even try to give it a decent amount of throttle.

I'm trying to figure out what is going on... its gotten progressively worse and tonight I've decided to just stop driving it completely until i eliminate the problem..

I've changed all the plugs and such..

Car does not throw a code until after about 10 minutes of it running, then the radiator fans kick on.

Any idea what could be the problem? Optispark, MAF sensor, 02 Sensors? anything?

 

Get PCM scanned & see what the code is, or just throw parts at it and hope to get lucky. Try running with the MAF unplugged & see if problem changes.

 

Problem got worse after running with the MAF unplugged for about a day.. fouled the plugs i think. But i've changed them since then.

 

what codes is it throwing? does it have a cat?

 

Since you don't want to get the car scanned, here is a list of parts you can try.
1) Clean air filter
2) Fuel pressure regulator
3) Check for stuck fuel injector
4) ECT, engine coolant temp sensor
5) Clean air filter
6) O2 sensors
7) MAF
8) TPS
9) Ignition module
10) Ignition coil
11) Optispak
13) PCM

There may be other problems, such as bad wiring & connectors, clogged cat, etc.. Get the car scanned & see what problem the PCM sees.

 

How old is your opti? That may have a little to do with it.

 

take it to advance auto parts, they can check it for free, thats if you have one near. more than likely it is you o2 sensor. I have alot of fuel going though my 94 mine is the o2 sensors, what kind of plugs did you put in it and what was the gap of the plugs?

 

Honestly, I have no idea how old the opti is.. I just bought the car maybe a month ago and the problem has progressively gotten worse.

As far as plugs go, I put NGK's in there gapped at .050

 

scann it for codes man. i think u can use the paper clip on the 94 and count the number of times the ses light blinks.

 

Yeah I've been trying to find somewhere that tells me how to use the paperclip method.. No luck so far :\

Hopefully I'm just looking in all the wrong places.