My 91's erratic idle help!!

[Rembly]

Took the my 2.2 wagon in to the shop to address my idle issue. Idle has been jumping around and while driving rpm's will drop 500 then jump back up and ill loose some power. Acceleration has been poor as well. Mechanic quoting me for a new idle motor for 500$..

Wondering if this is normal cost or if issue could be something else? Plus don't want to fork out 500$. I trust my mechanic has worked on my cars many times. But he doesn't know suby's like you guys!

[Legacy777]

The idle air control valve may be contributing to the poor idle, but it wouldn't cause poor acceleration and other drivability issues.

What other maintenance have you done recently? Does your 91 have a manual or auto transmission?

[Rembly]

Its auto. Ive had new CV joints, valve gaskets seals (I think), had tranny flushed. Also had the idle motor cleaned, twice. The first time my idle quit acting up only to slowly become more erratic over the next few weeks. I run premium Shell or Chevron gas and regular oil changes.

[Rembly]

172k all original motor.

[Legacy777]

Ok, well......the mass air flow sensor (MAF) can sometimes cause a loss of power and idle issues if it is dirty or bad. You could try using some MAF specific cleaner to clean it. That's just a guess without any additional troubleshooting info.

Also, I would recommend against running premium fuel. The engine has to work harder to combust the premium fuel. For a non-turbo engine, there's not much, if any benefit to running premium fuel unless the engine is tuned for it. I found that on my 90 Legacy (when I was non-turbo) it seemed to run best on mid-grade, 89 octane. I'd suggest running some regular fuel in it 87 and see how it drives....you could also try some mid-grade to see if that changes anything...

[Rembly]

It seems to get better mileage when I run premium. but I'll try running some mid-grade and inspect my MAF. Thanks Josh!

[jp233]

Running premium is not only a huge waste of money at the pump, it's not good for the motor either. There is no need to run it in an EJ22E. The compression ratio is not high enough to effectively keep burning it, and the motor/ECU will keep trying to burn it. Unless you're at absolute sea level, have perfect engine compression at sea level, have perfect spark plugs made for running that fuel and you're tuned for it....

I suggest cleaning the throttle body butterfly valve, check the PCV valve, clean the MAF, check the IAC, and most importantly ---- spark plugs! When plugs get old and the gap opens up, it is like clockwork around 27-29K miles that I will notice my idle will fluctuate - especially with Max AC on sitting at a red light in Drive (4AT) holding on the brake. This is with nearly 300K miles driven on one of these cars.

[afterthisnap]

Check your fuel injectors. 2 of mine were bad (sometimes only occasionally) and it caused similar symptoms in a 90 2.2 I was driving.