Hey Folks,

 

I got a new-to-me '97 Legacy Outback.  2.5 DOHC.  162k miles.  Runs pretty good minus a few little quirks -- I'd love some guidance.

 

- Power is inconsistent sometimes.  I step on the gas and it takes a few seconds to kinda get going.  Once it gets in the higher rpms (4k+ then it makes good power)

- Occasionally it will start bucking on light throttle, and then not hold an idle.  Car dies and I restart it and it works just fine again.

- No codes are thrown, no pending codes.

 

Things I've done:

- New plugs/wires

- replaced the MAF with another used one (so I'm not sure that tells us much) 

 

I have an OBDII scanner, but I have yet to be scanning it when it will start bucking and die, so I dont have much to go on.  

 

Was thinking O2 sensor?

 

Thoughts?  Thanks!

Edited November 25, 201411 yr by thedrew

Could be a sticking idle air control

you need to reliably confirm the timing belt and idlers were replaced 60K miles or so ago. If not, that is a ticking time bomb.

you need to reliably confirm the timing belt and idlers were replaced 60K miles or so ago. If not, that is a ticking time bomb.

 

I have no history on the vehicle.  Should I just do the timing belt and whatnot to be safe?

I have no history on the vehicle.  Should I just do the timing belt and whatnot to be safe?

 

definitely - if the timing system fails - you bend valves.

So I was driving it during lunch and i was doing it again and I was able to play with it before I hit a stop light and it died.

 

On light throttle, the bucking is very light.  I was holding 3k rpm and you could feel the power come on and off at like 1hz.

 

If you went farther into the throttle, the bucking would get alot more rough, same frequency.

 

I got some cleaner and a new gasket for the Idle valve, I'll clean it tonight. 

Check the TPS readout if it only happens at specific throttle settings.

Pull the inspection covers and inspect the belt. It is a really good idea to just replace the belt if there are any concerns about it

I suggest running a can of "dry gas", or adding one gallon of E-85 when refueling. You may have some water in your gas tank. The ethanol will clean out the water if there is any.

I cleaned the idle valve and so far its gone.  Thanks!