98' rodeo idles high rpm's of 1500 and down to 1000 sometimes i have replaced the egr, throttle position sensor, 6 new spark plugs, pcv, idle air valve, have sprayed all wire plug connector

SOURCE: I have replaced the throttle position sensor, egr

Check the Idle accelerator valve located on front side of throttle body, it is either stuck or needs cleaning real bad, this is what controls your idle speed, by letting small amount of air in. It has a plunger on it that moves back and forth slowly to adjust amount of air mixture, it is controlled by computer. Unplug it and just turn on key and check for voltage.This valve gets real gummed up, probably need to take apart throttle body and clean. HUNT

SOURCE: I have changed everything: Spark

There are three components that will enrich the fuel mix: 1)engine coolant temperature sensor. If this is not working or the signal is interrupted by a wire breakage then the engine will run rich. The coolant sensor informs the ECU (high resistance) that the engine is cold at start up and so the ECU responds by increasing the fuel injection cycle to enrich the fuel air mix. Later on as the engine warms the resistance of the coolant sensor drops and the injection cycle is reduced by the ECU. If the sensor is faulty or has become disconnected (wire break or corrosion of the socket pins) the ECU assumes that the engine remains 'cold' and the engine runs permanently rich. 2) O2 sensor, operates completely independently of the EGR, if it is faulty and signals 'too much oxygen' then the ECU will significantly enrich the fuel mix to try and balance what it thinks is an excess of air. 3) Fuel pressure regulator. If the diaphragm has broken or there is a leak in the vacuum line this will result in higher than needed fuel pressure in the fuel rail at idle. The vacuum line acts against the spring pressure holding the valve closed. At idle, the inlet vacuum pulls back on the diaphragm reducing the fuel pressure required to open the valve. Low fuel pressure coupled with short duration injection times will mean a lean mix at idle. If the vacuum is compromised or the diaphragm damaged then the increase in rail pressure will make the fuel mix very rich to point of flooding the engine

SOURCE: 1996 isuzu rodeo keeps reading

A misfire alarm typically means the coil pack mounted above the sparkplug indicated in the misfire had gone defective.

To test it, swap the coil pack with another cylinder, and see if the misfire goes from #2 to the cylinder you put it on.

If the misfire continues to be on #2, then consider changing the sparkplugs.

I hope this helps.