A little troubleshooting help..

[Tea Bag]

- Year
1995
- Make
Eagle (Mitsubishi)
- Model
Summit (Mirage)
- Engine (if there are different engines available)
1.8L SOHC
- Trim Level
ESi
- Modifications (if any)
none. Serviced at 100K with new serpentine belt and distributor kit w/ plugs and wires.
- Mileage
102K and change.

After the car warms up and you drive it for a while - when you press the clutch in the car idles extremely low, below the little tick between the 0 and the 1 on the tach that shows you where it should be when idling. It doesn't take much - sometimes just turning the wheel with the clutch in making a corner or just sitting at a light right when you roll up to it will kill this thing. It's happening frequently now, probably 3 or 4 times a day in an hour or two commute. The car fires right back up though as soon as you turn the key.

I have most of the weekend to pop the hood and troubleshoot so give me your best suggestions!

TIA

 

[Vette73]

Probable a Vacuum leak. Check for loose hoses (most very small) listen for a hissing sound while the motor is running.

The 2nd thing is the idle control valve. Clean it and also clean out the throttle body.


Do those 2 things and majority of the time will fix that problem.

 

[Vetterin]

Couldn't hurt to check/change the gas filter.

 

[cprince]

could also be the Idle Air Control Valve (IACV)--nevermind, Marlin already said it

 

[imported_Imp]

Could be anything...

Our old 1992-ish Dodge Spirit had the almost exact same problem. It ran fine for 20 minutes, then the 'check engine' light came on, and the power suddenly died. If you stepped on the brake for more than 5 seconds at a time, it would vibrate to hell, then stall. The car wouldn't accelerate, and it never went above 2000 Rpms. At rest, revs dipped lower than when it was freshly started.

To me, it felt like a transmission problem or even the computer 'throttling back' the engine (what do I know though?). Daddy, who was a mechanic for 30 years, said it could be an air filter problem, or the computer was fuxxored. However, he is also cheap, and a liar, probably hiding the truth to avoid having to pay for the repairs.

After a while, the breaks failed, so we scrapped the POS.

 

[cprince]

Originally posted by: Imp
Could be anything...

Our old 1992-ish Dodge Spirit had the almost exact same problem. It ran fine for 20 minutes, then the 'check engine' light came on, and the power suddenly died. If you stepped on the brake for more than 5 seconds at a time, it would vibrate to hell, then stall. The car wouldn't accelerate, and it never went above 2000 Rpms. At rest, revs dipped lower than when it was freshly started.

To me, it felt like a transmission problem or even the computer 'throttling back' the engine (what do I know though?). Daddy, who was a mechanic for 30 years, said it could be an air filter problem, or the computer was fuxxored. However, he is also cheap, and a liar, probably hiding the truth to avoid having to pay for the repairs.

After a while, the breaks failed, so we scrapped the POS.

My dad's '86 Civic had the exact same problem. It was the brake booster going bad and leaking engine vacuum.

 

[Tea Bag]

Probable a Vacuum leak. Check for loose hoses (most very small) listen for a hissing sound while the motor is running.

The 2nd thing is the idle control valve. Clean it and also clean out the throttle body.

Couldn't hurt to check/change the gas filter.

I bought a gas filter based on my brother's suggestion that's what it was but I didn't install it yet. The snow threw a monkey wrench in my plans so I'll have to get it in the garage tomorrow.

Thanks for the suggestions.

 

[CallMeJoe]

Originally posted by: Marlin1975
Probable a Vacuum leak. Check for loose hoses (most very small) listen for a hissing sound while the motor is running.
The 2nd thing is the idle control valve. Clean it and also clean out the throttle body.
Do those 2 things and majority of the time will fix that problem.

I'd suspect the idle control valve; in my experience a vacuum leak will result in the engine "hunting" or surging at idle, rather than just a low idle speed. Also, on most EFI engines, a vacuum leak large enough to significantly affect the idle speed will trigger a MAF fault.