2009 Toyota Corolla vibration after headgasket replacement

Hello! I own a ‘rare’ (or at least hard to find) 2009 Corolla XRS, dark grey with manual transmission, and I love it. I bought it from a Toyota dealer with warranty and 30k miles on it, and it now has 132,000… I do regular maintenance and keep it in top shape. Lately my local trusted shop told me there’s a developing leak and the car will need a new head gasket to avoid future damage. I said no last time, then yes this time. NOW that it’s been replaced, I feel a distinct vibration from the engine when accelerating (I feel it even more, when accelerating up hill)…if there’s a plastic bag on the passenger seat, I can see it shaking… it’s mostly only noticeable at certain RPM ranges (i’d say between 2 and 3 on the tach) and I feel it MOST in 2nd gear when giving it fuel, either light or heavy, and I still feel it, (although a little less) when continuing to accelerate into 3rd… There are no dash lights or error codes (yet), spark plugs were changed at 100k, my tires are good, tire alignments and balance have always been correct… and after putting 100k on this car, I know how it’s supposed to feel, and how it’s not supposed to feel. Of course, the shop who did the work says ’ there are many causes and it’s hard to know without any error codes, so when can you bring it in for us to fully diagnose it '? ----- with all that said, CAN replacing a head gasket cause vibrations? How or why? If not, what can? … Are plugs removed and replaced during the process? Is there anything else I should be thinking about as far as the potential cause… what something “suddenly” be causing what I feel? (‘suddenly’ has never been the way something goes wrong on my Toyota though, so it’s hard to believe that it’s a coincidence that the recent repair has-not caused the issue.) Sorry this is so wordy and thanks for reading, I look forward to any and all replies. (Also, my shop does warranty their work for 3 years / 36k miles, which is really great coverage, it they messed up I hope they’ll make it right at no cost to me). Bye for now, also I love your cartalk on the radio!

It could be a number of things, but would be great if it were a loose or poorly connect spark plug wire. If you’re completely in the right, be firm about them correcting the problem they created. Keep an eye on your fuel economy too.

There are no spark plug wires on this engine. It’s a “coil on plug” design, and the wiring harness is designed so that it’s impossible to mix up the connectors for the different cylinders.

A more logical explanation would be loose/worn motor mounts, warped/damaged crankshaft pulley or accessory pulley, or poor compression on one or more cylinders due to improper surface prep/gasket installation. Since there are no trouble codes, I’d suspect motor mounts or crankshaft pulley/accessory pulley.

I would have a compression test with a leak down test on all the cylinders to see if there is an imbalance. If one cylinder is unbalanced, see where the air is going on the leak down test. If the air is going externally into atmosphere; into the crankcase; or cooling system, the head gasket change was not done correctly.