fuel injectors or MAP?

[clutch-219]

Its a '97 2.2l sunfire, and im throwin two codes. first is PO304 which seems to be cylinder 4 misfire, and the second is PO107 which seems to be MAP/BARO low level input. The car will run, but has a haunting idle, and shakes violently, and usually dies. Now im getting spark to both 3 and 4 cylinders, however if i pull the plug wires off on those two cylinders when running, the idle doesnt change. which leads me to believe fuel injectors. So to test i swapped cylinder 1 and cyliner 4 injectors, and the car wont start now. leaving cylinder 1 and 3 with the "bad" injectors, which are the first two cylinders in the fireing order, probablly causing it not to start. So my question is that is it just the injectors that are bad, or does the MAP have something to do with it maybe? And if cylinder 3 appears to be dead as well, why wouldnt that be throwing a code? Any help/input would be greatly appreciated. Thanks -Ian-

[Helmuth48]

Here is some info.......

Repair
MAP SENSOR

Definition: Refers to a manifold absolute pressure sensor, a variable resistor used to monitor the difference in pressure between the intake manifold at outside atmosphere.

This information is used by the engine computer to monitor engine load (vacuum drops when the engine is under load or at wide open throttle). When the engine is under load, the computer may alter spark timing and the fuel mixture to improve performance and emissions.

OK....back up.....Find the source of the Misfire Code PO304 first...... Fuel Injectors.... most of ALL the one I have replaced were becasuse of Leakage...never have I found one bad, not that they dont. Clogged injectors will cause performance problems. I recommend a Can of SeaFoam every 3 tanks fulls. If you have good ears, you can hear the injectors firing, if not get a NOID light. Read this.... take care changing out injectors can damage o-rings and fill the cylinders with gas, now you can damage the motor !! I know I have done it !!!!!

http://www.asashop.org/autoinc/dec2000/mech.htm

Final, after all this, reset/clear the code and run the car again and see what you get now.

Good Luck, Cheers Mate, ..JzJzz