Siluck2

iTrader: (12)

So last weekend while tuning my cousins car, it started idling rough out of the blue. It happened after we flashed a map, but I think it was just a coincidence that it happened after flashing because we flashed back to a map that previously worked and still rough idle.

We found this broken sensor on the back of the intake manifold. Anyone know what sensor this is? Evap purge? Can this cause a rough/lean idle? All the lines on the EGR are hooked up.



Here is a vid of how it idles. You can see how it starts at ~14AFR when it starts and then creeps all the way lean. Any suggestions?

Revo15

iTrader: (19)

Start with a boost leak test and go from there.

Siluck2

iTrader: (12)

Well, it ran fine before, and then literally took a dump. I went and did a log, drove it back and parked it and it was running fine.

I have another video of the idle where it idles ok if I give it some gas, but it's still running lean on idle.

ak47po

iTrader: (3)

vac leak

Siluck2

iTrader: (12)

Do any of you know what sensor that is I posted a pic of?

ZanderGTS

iTrader: (1)

Im having the same issue in my X. Interested to know what ended up causing it.

Siluck2

iTrader: (12)

I think that broken sensor we found has something to do with EGR...So I think we are going to buy a block off plate and see if that fixes it.

spartiatis

iTrader: (3)

Im actualy having the exact same issue on SD and i cant figure it out. The car acts exactly like your car on idle and up to 2000rpm. When going over 2000rpm it is perfectly fine, cruising, boosting everything!

Siluck2

iTrader: (12)

Anyone else have any ideas? Could it be the EGR? We bought an EGR block off plate to try.

Klaiceps

iTrader: (18)

OP did you ever get this one figured out? I have the same exact symptoms as shown in the first video. I was also in the midst of playing with an aftermarket ECU and once I plugged my stock ECU back in, it started doing this. It starts, idle dips to 500 rpms and then dies. Throttle needs to be applied in order to keep the engine running but it's really lean. My car was running absolutely fine a few hours earlier and I'm having a hard time believing something mechanical is broken. Things I've done so far:

• Changed out ISC valve
• Replaced MAP sensor with a new one
• Swapped fuel pump with a known working one
• Checked fuel pressure via fuel pressure gauge
• Checked resistance on injectors, which are brand new
• Checked resistance on fuel relays
• Checked for blown fuses
• Flashed different maps
• Unplugged battery for 1 hour

I still need to do a boost leak, but if that checks out, then I really don't know what else could be wrong. I would appreciate any suggestions anyone can provide.

Bhsj13

I had the same thing happen to mine a couple weeks ago. turned out to be a bad MAP (losing signal randomly) and MAF. try getting someone else's MAF on first and see if it helps.

Klaiceps

iTrader: (18)

Thanks but I should have mentioned earlier I'm on SD, therefore no MAF. MAP sensor is brand new so a bad MAP sensor is ruled out.