Switched to synthetic oil, now 'bouncy' idle, 2011 V6

2011 V6 with 70,000 miles.
Took it to the shop or dealer for an oil change every 5k miles with conventional oil, but decided to start changing my own oil. I followed the sticky thread here, which was a great help. I put in 5.5 quarts of Mobil1 5W-30 and a Wix 51438XP oil filter. Fresh drain gasket, oil levels look good.
Symptoms: first few minutes, the idle wasn't rough, but very bouncy. Best way to describe it is smooth for about 3-5 seconds, then a couple bouncy moments, then smooth, then bouncy again. No visible change in RPM, resting around 500. The engine also raced a couple times at low speeds between gears driving around the neighborhood, but that has since subsided. On a restart after dropping off the old oil for recycling, the engine didn't catch the first time I tried to start it, but fired up like normal right away on the second try. Didn't have this problem again. No noticeable differences cruising at 45 and 75mph, but the bouncy idle comes back again at stoplights. I drove around for about an hour including some errands, and oil level looked good.
Is there a 'break in period' switching to synthetic from conventional? Am I missing something else? I didn't touch anything else while working on it. It was 60 degrees here today, so no weather factors. Will have to wait until tomorrow for another cold start.
Thanks.

 

Still a little rough idling this morning after a cold start, but operation is smooth. Any thoughts?

 

A oil change to synthetic will not cause any of the issues you listed. A wire accidentally pulled from something will. Are you getting any codes?

Did you fill up right around the same time you changed the oil?

 

When I switched to synthetic my truck seemed to idle just a little faster opposed to dino oil. Switching from dino to synthetic should not cause the problems you describe. I don't claim to be an expert so maybe someone else will chime in. I would suggest posting this on Bob is the Oil Guy website. If it's oil related someone there will be able to help, they take oil and oil related issues to an extreme level.
https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=cfrm

 

Not showing any lights on the dash, and I don't have a diagnostic reader. Previous fill up was about 60 miles before the oil change, and said symptoms were not present. I'm in agreement in thinking an oil change wouldn't cause what I'm experiencing.

 

Thanks. I'll go poke around.

 

Sounds like a vacuum leak. Check if you might have disturbed a line. Or, like previous post, you accidentally disconnected a sensor. NO way that changing to syn oil will affect your idle like that.

 

I switched to synthetic on my 2015 at the first oil change (only 2000 miles @ 6 months) and did not see anything weird BUT. I had issues with my olden Toyota at an oil change. The crank case breather did not like the synthetic and it turned out it was a clean out of that whole system, valve and tube - now that was on a carb 22r engine but you might want to look at the smog valves and clean them especially at low rpm. I have always changed the oil before a smog test as I found the dissolved crap always messed up our cars.

 

Checked everything I could see in the engine bay, top and bottom. May end up taking it in to the shop, but will give it a few days in hopes things settle down.

 

Good luck OP, let us know how you make out

 

Coincidence, not oil.

Unless, as someone mentioned, a wire was compromised in the process.

The PS idle speed adjust comes to mind. Even if in place, it may need cleaning.

Also, when was the last time the throttle body was cleaned? Air leaking around the butterfly at idle due to dirt build up can cause erratic running. Can't hurt to try, but be sure to use TB cleaner, not carb cleaner.

 

X2 on the vacuum leak.

 

I've been told the 1st oil change after switching to synthetic is short mileage. I don't remember the number.
I read online Mobil1 and others aren't true synthetic. They are oil companies.

When a previous mechanic, in Seattle area, used synthetic, it was AMSOIL.

Ken in NC

 

I'll bet since this is your first diy oil change you are just being paranoid. It's all in your head man.

 

x3 on vacuum leak.

 

Make sure the oil cap gasket is clean and the cap is tight.

Make sure the dipstick is firmly seated in the tube.

 

There isnt a chance u drained the tranny pan, and then put 5.5 qt of new oil on top of the 5.5 qts of old oil is there? Wouldnt be the first time and 11 qt of oil would prolly make some wierd stuff happen, also tranny being 3 qt low might explain some stuff too

 

This sounds like a plan get some starting fluid and check your lines but before make sure you didn't bump an electrical connector so it is not making good connection. I have a 2011 I bought brand new and run synth in it have been since the second oil change. I can tell you something I learned with the first Toyota I owned a RAV 4 the idle always seemed HIGH when it was cold IE winter time. Checked with other owners and several mechanics all said yep normal but it did not bounce idle.

Cypher

 

This answer is the winner. I am the loser. Truck is quarantined in the garage until I can get more ATF Monday when the dealership parts department opens up. Will drain my oil pan too and start fresh. Merry Christmas everyone! @yota243 wins something.

 

Wow, what a good thing that you were thinking outside the box.