'95 Subaru Liberty - Temp Gauge fluctuates and Revs jump

[Sezb10]

Hi Guys,

 

 

I have a 1995 Subaru Liberty Heritage, 2.2l Auto, 190k on the clock. 

 

 

About 3 months ago I had a major 6year service on it - about a week later the engine light came on, took it back to the mechanic and they changed an ignition coil and the alternator.

 

Recently I have been having an issue when I drive on the highway - the temp gauge appears to fluctuate - it will go up near max but just as quickly comes back down to normal temp again.

A couple of days ago I came off the highway and was idling at a red light - the revs jumped from the normal 500 to over 1k for a couple of seconds. The temp gauge was showing at almost max (car did not appear to be overheating though and no issue with the coolant level).

This has happened on a couple of occasions - always seems to be after I have driven on the highway (which I only do approx. once a month).

 

Also a few days ago sitting at a red light the revs jumped up for a few seconds and engine light came on for about 30 seconds (engine light not on at the moment).

 

 

 

Any ideas of what could be going on??  Would really appreciate it! :-)

 

[1 Lucky Texan]

rebuilt alternator could be bad - that system needs to be checked, overcharging a battery is not good. Could also be a bad/intermittent ground wire somewhere. They can need to be 'refreshed' on older cars.

 

is the check engine light on? might check for pending codes anyway (is it OBD I ?, will the old system store pending codes?)

Edited November 11, 2015 by 1 Lucky Texan

[Sezb10]

Thanks for your response.  Check engine light only came on for about 30seconds when idling and revs jumped up for a couple of seconds - light is no longer on. 

I'm presume it's OBD I but not 100% sure.

 

I'm leaning towards Coolant Sensor at this stage..have had a couple of instances on really cold mornings when I haven't let the engine warm up - the car has struggled at low idle (at stop signs/red lights) where the car has effectively stalled/lost all power (I'm guessing probably flooded engine).

 

I took it into the mechanics to do a diagnostic scan and they reckon no codes came up.  Possible dodgy mechanic as I had a mate plug in 2 different scanner tools and they couldn't get any power through the dash to the scanner?!

 

 

Not too good with the electrics/computer side of things unfortunately.  But done all the mechanical checks and can't identify any issues elsewhere that would cause it.