Injectors are one of the most reliable parts on the car. Testing injectors takes some special tools (injector pulser, and fuel pressure gage), so does testing the signal to the injectors (noid light). If it seams to be having problems changing load conditions it could be a MAP or TPS. Checking the map sensor requires a vacuum pump and multimeter. Checking the TPS requires just a multimeter. IF one of those sensors is messed up and reporting an improper signal but not so far out of range to set a code, it will cause weird drivability problems. One kind of redneck mechanic approach to testing a sensor without the proper tools is to disconnect it. Disconneting a sensor will set the check engine light, but usually the computer will compensate to some degree in a "limp home" mode. I wouldn't recommend driving around for any length of time on a disconnected sensor, but it will give you a good idea if the sensor is bad.

For example. If you had a lazy MAP sensor that was not reporting a high enough voltage with no vacuum applied. It would cause the engine to stumble at WOT. If you disconnect the MAP sensor, the low speed drivability will go nuts, but under WOT, the engine would perform much better.

Unfortunately with this approach, you need to have a pretty good idea what is broken. If you start randomly unplugging sensors with out a rhyme or reason, the sensor you unplug may effect more than just what you are looking for.

For example, if you had a lazy O2 sensor that was tending lean and you unplugged the CTS not the O2 sensor, the computer would set a code and run in open loop operation. In open loop the computer would ignore the O2 sensor and run some basic programming that give decent performance. This in turn would cause the symptoms of a rich engine to go away. Not because you disconnected the bad sensor, but because you tripped the computer into running in a different mode.

Basically what I'm saying is, if you wanna try the backyard mechanic approach, be wary of the results and conclusions. That said If you wanna give it a go...

I'd disconnect the O2 sensor to start with. It will force the computer to run basic programming looking at the MAP, TPS, CTS, and CPS. It will set a check engine light, but it will not try and trim the fuel for best economy/emissions. If this helps it, you may wanna think about an O2 sensor. If it doesn't, it is probably one of the aforementioned sensors. In that case, based on the symptoms I'd try the TPS or MAP.

If you want to try it the cheap way, post your results. Otherwise, it may be time for a shop to check it out...

Either way good luck <img src="/forums/images/graemlins/cheers.gif" alt="" />