90 Jeep Cherokee, will idle good then die down an pick back up
I have a 1990 jeep cherokee with straight 6 it will crank up an idle fine then after about 45 seconds it will turn to a rough idle for about 10-15 seconds then pick back up to normal again. Any suggestions thanx
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mine also will quit going down the road, and idles high at times, or idles low, like having a mine of it's own. possibly idle air speed solenoid (which i replaced on mine) and still does this. another tech said only factory solenoid will "talk" to ecm properly?
The idle relearn needs reset. Keep your foot on the gas at about 900 rpm. Make it idle for about 5-6 minutes. Slowly ease up on the gas until it will idle on it's own, it might take a while. After you get it to idle, it might be idling real low, but on its own, Let it sit and idle until for 20 minutes. After that it should be back to normal. You will have to do this every time you have the battery unhooked for a while.
if the motor turn over but will not start try looking at the cps(crank position sensor)it would create a no spark condition. its located at the back of the engine right at the bell housing for the transmission.you can test it with an ohms meter or just replace it.
any leaks in intake or exhaust upstream of the sensors, sparkplug
condition and engine controls/sensors for out of range operation
(including fuel pressure and condition of regulator)
IAC should be cleaned and checked as this can cause poor idle and shut
down. I'm not saying not to change O2 sensors, but unless everything
else if OK, it probably won't help.