Mark,

EVERYONE in this forum totally respects Turbotrix. We haven't seen the guy's car, and are just trying to help however possible over the internet. According to the post, the guy threw the CEL before he DC'd the battery, and I'd agree that it'd be nice to see what that CEL is too, as I agree its the problem. Nobody here is questioning the quality of your work, but we want to help the guy figure out why his car is acting goofy.

We'er all friends here; nobody's saying you messed up the car!

 

I disconnected the battery and hit the brake like Mark suggested. The car is idling, but it's rougher than normal. Starts off low after starting the car. After about 10 seconds, it's idling around 800 rpms, but fluctuates more than normal. I'll need to have someone check the CEL code. The weird thing is, it was running fine after throwing the CEL on the trip back. Only started running bad after disconnecting the battery. I had just filled up with gas minutes before. Maybe it's bad fuel. It's acting like it did before throwing the "random misfire" code over the winter.

I also checked the plugs and the cam timing. Everything looked fine.

 

The stalling issue was back this morning. Sounds like there's a mild backfire when shifting from 1 - 2. Overall, it's like the car is missing badly. The idle is very rough. I'll try to have the local dealer read the code today.

 

I'd try to not drive it very much -or not at all if possible- until you figure out what is going on.

 

Is it possible that the throttle body resets itself after you disconnect the power? I had previously made some idle adjustments to the throttle body to help the cam idle. Yesterday, I bumped up the idle before leaving work. It didn't stall on the drive home. After disconnecting the battery last night, I had stalling issues. When I owned a GTI, it would automatically reset the throttle position sensor when you disconnected the battery.

 

Mine has never done this with over 10 resets for cam gears, stereo head unit, etc. But in contrast, I've never messed with the throttle body adjustments either.

 

My guess is that's the culprit, since your idle has gone bad to worse from tampering with it. Fix the adjustment. I had a similar situation. I have an OBDII scanner and with it I saw that my throttle plate was not reading 100% at WOT. You can do this without turning on the car, just flip the ignition to ON and read the scanner while pushing on the throttle all the way. Anyways, mine was reading 98% so I loosen up the throttle position sensor to adjust it so that it would read 100%. But before fine tuning it's position I swung it all over the place to see how much adjustment there was in it. Needless to say this threw on a CEL for the TPS being off. I position the TPS to 100% at WOT, cleared the code and haven't seen it since.

 

I think you're correct. It must reset when the power is disconnected. I made a small idle adjustment before leaving work. Opened it up about 1/4 turn. It was fine on the drive home. No stalling issues.

 

DC the battery terminal and hold the brake pedal to total drain any type of current that may be left in the system. Then reconnect the battery start the car and let it idle for about 10 mins, but make sure all a/c and radio is turned off and do not touch the gas (if you touch the gas the whole thing must be started over). But this must be done with the engine completly cold in order to work once cars idle is stabilized and has sat for some time shut off the car. Wait for a few seconds and restart the car, it should idle and perform normal now. All evo ecus must re-learn the idle value for the idle air control motor over after a DC is performed. Some evos are just more sensitive than others to it which is why you must perform this procedure. This is nothing new when I was working for mitsu it was not uncommon to see this happen. Most of the time the ECU will pick it up and re-learn if it doesn't you will need to slowly turn out the idle air screw located on the top firewall side of the throttle body and repeat the above steps untill it does.

 

How is the car now?

Just Curious

 

The car is working fine now. Just took a slight idle adjustment.