Stock motor. Earlier today, the idle speed started to drop really low and the idle became very rough as a result. As the day went on, I started having to hold the gas down at stoplights. Now, it dies if I don't keep my foot on the gas to keep it running.

At startup, the engine will idle on its own, but once you touch the gas and break out of that startup mode, it won't hold idle anymore.

Otherwise seems to be running at least close to normal.

Already checked the plugs and they're all good. Gave the map sensor a whack, but that didn't fix it.

Used Chevron fuel system cleaner last week and I'm afraid that might have loosened up some gunk.

Ideas?

 

I think it may be the muffler bearings

 

Sounds ignition related. Check your coilpacks, but you would know based off the plugs, which I know you know how to read.


Or it might be a cracked vacuum hose somewhere.

Do you have a set of stock injectors to swap in for testing purposes?

 

Most likely a Faulty IAC.

You can unbolt it from the intake manifold and spray it out with carb cleaner. If the idle comes back you're lucky. usually they will start idle surging and then you have to replace it.

 

Asura: Spark plugs looked fine, so I don't think it's ignition. HOWEVER, the roughness of the idle does lend to your theory as opposed to an air or fuel issue.

Slows2k: I like where your head's at. That's going to be the next thing I check.

I just recently moved back to LA so I'm back to not having a regular garage and all my tools are back to my mom's house in Riverside. As a result, I'm sorta trying to play MacGyver in the underground parking at my apartment and this is quite a pain to work on. I took the fuel pump/filter assembly out just now to make sure there wasn't some big piece of junk stuck to it and clogging it. No such luck, everything looked fine.

From there, I went to the front of the car and started snooping around. I noticed that upper half of my AEM V1 intake had slipped out of the fitting that connects it to the bottom half. No idea how long it was like that, but the throttle body was a bit dirty. I reconnected that and cleaned out the TB a bit.

After that, I started it up and it idles now (not really sure why). If I rev it up, as it returns to idle, the idle speed will drop too low and then it will pick back up and normalize. This seems in line with slows2k's theory...

I'm off to Vegas tomorrow, so I'll update this early next week after I have a chance to tinker more.

 

let us know what it is when you find out.

 

Map Whack?

 

Vegas...Shiny Disco Ballz

 

Problem with the idle air control valve? (IACV)

Bit of dirt caught in it can cause this, had a similar problem on my DC5-R before...

 

SRL311TOO - map whack was the second thing I tried (see first post).

Mbmc - yes, this is probably it since the intake had gotten disconnected from the filter element. The TB was dirty, so I'm sure the IACV was also. I wiped out the TB a bit last night. After that, it started idling almost right, but not quite. This morning it drove without any problem at all.

When I get back next week, I will get back in there and clean things out a bit more thoroughly - particularly the IACV. At this point though, I think the source of the problem is indeed either a dirty IACV or dirty TB.