High idle (2,000rpm) on '99 Legacy

[zyewdall]

1999 Brighton, 2.2 liter, 5MT, about 70k on the engine, 150lk on the car.

 

All of a sudden, yesterday, it decided that the idle should be at 2000rpm instead of 750 where it usually is. Does it even after being turned off and restarted, and whether it's warm or cold. A/C brings it down to around 1,600, but still high. I changed the oil about a week ago and switched to synthetic, but other than that, and changing the tie rods, I haven't done anything recently to it.... no check engine lights or codes... what could be causing this? Still seems to run great otherwise -- no stumbling, hesitation, surging, or other issues.

 

???

[bstone]

The throttle cable might be tugging it open? Probably not the issue, tho.

 

Might be a vacuum leak.

 

Pull the - battery cable for 10 minutes. See if that helps.

[wtdash]

Leaning toward a Vac leak too. Possibly you bumped something that finally came loose?

 

That is a Phase 2, EJ22, so not sure what sensors changed from the EJ22e, but the TPS/IAC were on the early years.

 

The coolant temp sensor can also go bad and seems to cause frequent issues w/idle.

 

If it's still a MAF-based system, I'd clean the MAF - carefully! - read up on here.

 

GL,

Td

[Fairtax4me]

The throttle cable is very easy to check. Simply push on the throttle lever and see if you can make it close any further. Cable issues are not common, but do happen. I saw one that would only happen when hot, but the throttle would stick at about 3500 rpm. Tech replaced the throttle cable and all was well.

[WoodsWagon]

The idle air control motor can get gummed up and stick, causing a high idle. It's a 1" black rubber hose connecting to the IAC on the side of intake just below the throttle body on the passenger side. You can pull the hose off and spray some carb cleaner in there and possibly gently poke it with a screwdriver to get it worked loose again.

 

One other possibility is the cruise control actuator. The cable can pop loose from the front of the actuator can if you accidentally lean on it, and that will hold the throttle partway open. It just clips back into place if you knocked it loose.

[zyewdall]

I'm suspecting something with the iAC or MAF..... though, today, it's decided that aroudn 1400 rpm is where the idle is, instead of 2,000.... I'll get some cleaner later today and mess with it.

 

Thanks for the suggestions.

 

Z

[zyewdall]

Well.... didn't do anything to it yet, and the idle is back at 750, right where it used to be. I took it on about a 300 mile trip over the weekend, and the only issue was when I started it Sunday afternoon to come back, it sounded like I had a pretty loud rod knock for about 2 or 3 seconds before going back to normal, right after starting it after it sat for about two days. Hmmmm..... demons anyone?

[1-3-2-4]

I remember my IAC was so bad on my 95 I had to take it off (need new replacement gasket) and I used a whole can of carb cleaner on it.

 

my 97 is the same way sometimes I will get around to doing that when I pull the motor.

[WoodsWagon]

it sounded like I had a pretty loud rod knock for about 2 or 3 seconds before going back to normal, right after starting it after it sat for about two days.

Failing anti-drainback valve in the oil filter. It's not keeping oil up in the galleries of the block, so the bearings are running dry until the pump can fill it all back up. Put on a better quality oil filter and that will go away. Probably has a FRAM on it now, right?