My car has been driving funny with a light load on the engine. Its somewhat like a hesitation while driving around 2500rpms, the rpms jump up 300 more or so. It doesnt allways do such is why its kinda hard to tell what the problem is. I have experienced this for a few weeks. I dont think its a tuning issue sence the car ran right for a week or so after the car was tuned. Sometimes after I start the car the rpms jump up and down. I dont have twins anymore so its not turbo issue. I kinda think its the o2 sensor becuase I dont know what else it could be.

 

smart *** answer: change it they are cheap!

they basically get slower over time, and they also loose their full range. its also possible it got coated with something (lead? cooant? ???) and just stopped working

 

OK kids my name is Steve Gambone and I do this for a liven, a drive tech.

The most importent tool to use is a scope, UEI makes one and wiil cost you about 1150$ you can find them cheaper. With this you will be tapping into the signel wire off the O2 sensor and you will be looking for .1 to .9 volteg. Race the motor up 3k rpm for 60 sec let go of the throttl and watch the the volteg signel drop like a rock to .1 , hit the throttl and watch go stright up like a rocket, that says it's working and most likly your fuel system is OK

 

Part II, the above is a test to see if the O2 works, if so then we should be able to get a switching action on its own. With the scope hook up with real long leads we go for a test drive a steady 40 mph will do and we are looking for a up and down swing .1 to.9 or so dosen't have to be rite on as long as it goes past .5 on it's way up and down. if not something is wrong. a good digatel volt meter will work but this will only tell you that the O2 can put out volteg and that it is between .1 and .9 where god only knowe becouse a volt meter is not fast enough to keep up.