i have a 94 ls and ever since the previous owner replaced the o2 sensor the check engine light comes on after it warms up from being cold but if you turn off the motor and restart the engine it goes away sometimes it does not restart right away u have to leave it turned off for awhile before it starts again. also if while going down the road you quickly take the key from run to acc and back to run really fast the light will go away but sometimes it is like the engine loose power it can be in the run position after i do the flip thing quick the check engine light goes away but no matter how hard i push the gas peddle i keep loosing rpms. can anyone explain what is the cause of the restart problem and the check engine light based on what i have wrote or give me a general direction

 

Good grief. Don't do the flip thing! That's an old trick to turn off a check engine light but it's not going to solve your problem!

You need to check out what your ecu engine code is and then figure out what the problem is. Look at your ecu. If you don't know how to pull codes check out the FAQ. It has the information and also what ecu code goes to what problem. Once you've established that you'll have an idea of what route to take to fix the problem.

Seriously, stop doing the flip off/on thing.
-Rik

 

it was throwing the o2 code but it before the replacement and after
but that does not explain it not starting right away after i shut down or do the flipy thing

 

So is the CEL on right now?

If so pull the code and tell us what it is.

How to check CEL

 

The car not starting isnt an O2 issue. Sounds like your friend might have messed with something else in the process, or pulled a wire lose. I know I have had an engine ground that was about to break cause this before. Simply replaced the ground and it worked perfectly with no future issues.