Cold start burbling

Are you saying within a few seconds/minutes it goes away? I think the roughness on start up is a result of the calibration. Start-up fueling and ignition timing is a bit of a black art that they calibration engineers more than likely figured out by trial-and-error. It will be specific to an engine, and I don't think any oil choice will fix it. It is more likely that your engine/transmission mounts are worn, allowing more engine movement or more transfer of vibration to the cab.

But if the engine and transmission mounts are worn, wouldn't the heavy vibrations continue at Normal Operating Temperature too? It goes away after a few minutes of either warm up or normal driving. If I'm driving in temperatures below 30 degrees, I always let it warm up until I see the needle on the temp gauge flinch upwards slightly, so I feel comfortable that most internals have been soaked in oil. After this time, I DO NOT feel any excess vibration when stopped at a traffic light or stop sign. Does this shed any more light on the issue?

I have a 2001 Forester and I live in Dallas so probably slightly colder than your San Antonio, TX location. I usually just start it and drive away. No issues, I run either Mobil 1 5w-30 or Rotella T6 5W-40. I doubt its the engine mounts, I have 212,000 miles on my Forester and never changed engine mounts. Also as you have pointed out it goes away after its warmed up. How many miles on your Forester? Have you changed spark plugs recently, have you changed spark plug cables. Other than cold, temps what about humidity? Any CEL?

RyanT said:

It is more likely that your engine/transmission mounts are worn, allowing more engine movement or more transfer of vibration to the cab.

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bman400 said:

...No issues, I run either Mobil 1 5w-30 or Rotella T6 5W-40..... Have you changed spark plugs recently, have you changed spark plug cables. Other than cold, temps what about humidity? Any CEL?

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These are what I'd check on, keep us updated.

I did change the coil pack last year... because I'm still chasing another occasional winter problem of a P0303 cylinder #3 misfire. So what are the best plug wires to buy from the regular parts stores? I think I'm running DeathZone auto parts house brand wires for a few years now... maybe it is time to change those. Plugs? Standard copper core NGK I assume?

SueBrew said:

I did change the coil pack last year... because I'm still chasing another occasional winter problem of a P0303 cylinder #3 misfire. So what are the best plug wires to buy from the regular parts stores? I think I'm running DeathZone auto parts house brand wires for a few years now... maybe it is time to change those. Plugs? Standard copper core NGK I assume?

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I would get some NGK Plug wires and NGK copper or iridium IX plugs. The copper ones are fine up to about 30,000 miles.

These are the plug wires I bought in 2013: https://smile.amazon.com/NGK-FX58-P...-1-422-22-1-0&sr=1-1&ymm=2001:subaru:forester

Always use quality parts because they fit/work better and last longer. NGK is good and Bman400 suggested some nice plugs and wires that I'd use.

I just ordered NGK plug wire set from Death zone auto parts... $38.00!!! Who woulda thought it was such a steal compared to other shops?! Some of you may want to rush out and stock up on that now!!

Good purchase. How's the cap/rotor and plugs, whens' last time replaced and how many miles since then?

Since this issue is only on cold starts, I would test or replace the coolant temp sensor (NOT the sender, but the sensor).

SueBrew said:

But if the engine and transmission mounts are worn, wouldn't the heavy vibrations continue at Normal Operating Temperature too? It goes away after a few minutes of either warm up or normal driving. If I'm driving in temperatures below 30 degrees, I always let it warm up until I see the needle on the temp gauge flinch upwards slightly, so I feel comfortable that most internals have been soaked in oil. After this time, I DO NOT feel any excess vibration when stopped at a traffic light or stop sign. Does this shed any more light on the issue?

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Following your thoughts. Subaru's are inherently smooth 4 cylinder engines and perfectly balanced. They are so smooth that the designers did not need to design balancing shafts normally found on I-4 (FWD) 4 cylinder engines like Honda Civics, etc...The smoothness comes from each cylinder on each side of the engine moving together with each other and therefore balancing each other out.

And as you pointed out, this vibration disappears when its has warmed up.

Have you looked at the plugs color/colour when you pulled them out? Are they dry? Wet? are they a light tan/brown in color/colour? Or are they wet, black.

My 2001 unit is on its 2nd set of plug wires, 3rd if you include factory, probably 3rd set of spark plugs. Still the original coil pack from the factory.