jeep surge idle
Seems like my 09 grand cherokee seems to surge in temperatures above 40 at idle. What i mean is when idling at its normal 550-600 range (at least thats where mine is) it will sometimes drop down from that point to like 450 rpm but bring itself right back up if the temperature is above 40 degrees. If its below 40, which it currently is 30 degrees right now in new york, it will idle fine and stay at that 550-600rpm range with no trouble. Any ideas? replaced a lot of things over the past month cause i had some idle issues including: camshaft, cleaned throttle body, spark plugs, checked transmission fluid level, map sensor, lcv valve, erg valve, and ecu reflashed at dealer last week. Dealer said its just the way the engine is and will do this from time to time. Honestly as long as it doesn't stall on me, which it hasn't, it doesn't really bother me. One time it dropped down to about 300 rpm and restarted itself but that was before the reflash and a few things getting replaced. Gonna replace the crankshaft sensor tomorrow but other than that, can't think of what else could cause this. anyone have any ideas or currently have this problem? its the 3.7 engine btw.