I have a 97 Ranger 2.3 with a rough idle and stalling issue. The trouble code is P0303 (cylinder 3 misfire). I have done everything I know to do. I have taken it to 2 shops and can't figure it out. I replaced the fuel injectors and upstream 02 sensor and the cel light is now off but it still runs the same.(Rough idle, sputtering) So far, this is what I've done:
1. Replaced fuel pump
2. Replaced fuel filter
3.Replaced Air filter
4. Replaced entire EGR system
5. Replaced TPS
6. Replaced IAC valve
7. Replaced timing belt
8. Engine temp. sensor.
9. Replaced fuel injectors
10. Replaced upstream 02 sensor
11. Cleaned MAF
12. Cleaned throttle body
13. Replaced plugs and wires
14. Replaced both coil packs

Any help would be appreciated. Thanks in advance.

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1997 ranger xlt 2.3L 2wd

Have you ran a compression test?

I'm not exactly sure on how to do a compression test. Is that where you use a gauge in place of the plugs? If so, what am I looking for? Btw thanks for your reply

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1997 ranger xlt 2.3L 2wd

All cylinders should have a close reading, if one is considerably lower, that would be cause for missfire and bad running.

I will try that my next day off.

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1997 ranger xlt 2.3L 2wd