Low idle rpm puzzle not the classic problem

[scottywilliams]

I've got an interesting one for you guys. My protege 2.0 idles under 500, sometimes 300 like it's gonna crap out, but it hasn't stalled yet. been driving like this for about a week now. When I pull into the driveway after work today, i started hearing this clicking noise, and I thought oh crap it better not be knocking. It wasn't, turns out the EGR vacuum control solenoid was switching on and off rapidly, at 500 rpm!? And then it would stop clicking, a few seconds after it does,rpm goes down again probably in the 300's, then the solenoid kicks back on. This is a big puzzle for me because I thought the solenoid doesnt activate the EGR system until around 2000rpm. No cracks in the intake hose. I should mention though that my battery died completely a week ago, and had to trickle charge it overnight. It's been testing fine at 12.5 V, and over 14V when engine is on. Some people suggest that the rough idle is likely because of the dead battery, and that disconnecting the battery to restart the computer could help. I'm going to try that and get back to you guys bout result. Could anyone tell me why would the EGR vacuum solenoid be activating at low rpm though? Does it happen to anyone but without the battery problem?

 

[kms1990]

your egr valve maybe stuck open if you take it off you have to replace the gasket try running some seafoam through the vacuum line (brake booster hose) while its idling, very slowly about 1/3-1/2 can and put rest in gas tank. turn it off let it sit for 30+ mins. then go drive it fast for a few miles. that would be where i would start. maybe a crusted up egr valve a sticking one, an egr leak or a vacuum leak, is the check engine light on? if so get the codes read. check all your vacuum lines and clean your mass air flow sensor with some mass air flow sensor cleaner. if none of that helps your going to ahve to start replacing parts.

 

[MaxPower]

Disconnect the electrical connector to the EGR valve to disable it (CEL will turn on). If the rough idle goes away, the problem is the EGR.