check engine light Options

[6strngs]

so, the check engine light on my car lit up. The car still ran fine and everything, I stopped and restarted a couple times today with no problems with anything, everything seemed normal. I think I know what caused it. about a week or two ago, I decided to unplug the hose connecting the EGR to it's source of vacuum. I read about it on mr2oc.com in one of the threads about NA 5sfe power. anyway, after driving around like that for a while, I decided that there was no noticable difference and it just made a wierd sound before 3-4K rpms and might've also been giving me a slightly high idle. so I decided to plug it back in today. but after I did, I noticed that after a while that the yellow light that had lit up on my dash wasn't the fuel light like I thought, but the check engine light. I wanted to get a paper clip and see if I could get a code for it, but I was with my girlfriend today, so I was... occupied. So I was gonna check it right after I got home from dropping her off, but the light went off on my way home. so, the question is, could it have been from reconnecting the EGR? and why would it throw the light to reconnect it? if anything, wouldn't it have thrown the light by disconnecting it?

[alltracman78]

yep

Exhaust Gas Recirculation [valve].
It recirculates exhaust gas to your intake man. Which is then sucked into your cylinders. Exhaust gas in your combustion chamber = less combustion = cooler combustion temps.

Cooler temps mean less NOx is formed. NOx is oxides of Nitrogen for those of you that remember chemistry.
Smog/acid rain.

It's only open while you are at part throttle. Never during WOT or idle. Unless something is wrong. A stuck open EGR valve can cause a rough idle, or even make the engine die.

6strngs-You don't need a resistor IIRC. You just need to jump the connector for your EGR temp sensor.
Your problem might be caused by clogged passages in the head/intake man/EGR tube [below the EGR valve], and not the actual EGR valve itself.

[6strngs]

yep

Exhaust Gas Recirculation [valve].
It recirculates exhaust gas to your intake man. Which is then sucked into your cylinders. Exhaust gas in your combustion chamber = less combustion = cooler combustion temps.

Cooler temps mean less NOx is formed. NOx is oxides of Nitrogen for those of you that remember chemistry.
Smog/acid rain.

It's only open while you are at part throttle. Never during WOT or idle. Unless something is wrong. A stuck open EGR valve can cause a rough idle, or even make the engine die.

6strngs-You don't need a resistor IIRC. You just need to jump the connector for your EGR temp sensor.
Your problem might be caused by clogged passages in the head/intake man/EGR tube [below the EGR valve], and not the actual EGR valve itself.

I did clean the tube that came from the bottom of the valve. I also cleaned the inlet where it connects to the throttle body. and I cleaned the filter for the vacuum valve thingy (the valve that sits next to the EGR valve on the intake manifold) I also cleaned off the tip of the sensor because it was crusted over with grime...