2006 2.4L 4-SP Auto Trans 2WD Highlander EVAP Mystery - Dash Lights Galore & 5 Mechanics Later

Greetings! My husband and I are fairly new to Scotty's useful videos on Youtube, but are catching up. Went several pages in reading other EVAP codes posts. Not quite sure our mystery is solved based on what I have read so far. Please allow me to explain. And also to preface things and provide as much info as possible. I am by no means any sort of mechanic, but I do try to have a little knowledge of the things I drive. But that is LIMITED! Please forgive my errors and ignorance. My husband and I don't do many repairs ourselves outside of body work, radios, interior items, etc. but we do try to acquire knowledge with every new issue in maintaining our used vehicle over the decades. So here goes...

We purchased our first Toyota in the winter of 2020 when EVERYTHING used was doubled in price from 2019. We had no choice however, as an angry driver plowed backwards into our mint condition vintage Mercy Grand Marquis from her driveway. That car was was our only vehicle and we needed a replacement fast. My 91 yr old Grandfather (may he now RIP) had told me for years to buy a Toyota. So we did. We found ourselves a one owner 2006 Highlander within budget and fell in love with its simplicity and comfort. Test drove it, got the computer read for stored codes and did my research. Seemed like the fairest price given the circumstances and limited inventory everywhere (I literally drove to 5 states trying to find a vehicle). 125K miles for $9500. It is the base model with the 2.4L 4-speed automatic transmission, 2WD. Nothing fancy, should be simple to care for. Or so I am hoping.

It is immaculate inside and out and finding out just about everything is original (made in Japan) had us feeling confident we made a good purchase. However, the vehicle was involved in a head on wreck in 2014 by original owner and had to have a new radiator and new headlights. But alas, the glee did not last long and the mystery began about 200 miles into driving it. After we got back to our state with the vehicle and got tags for it, we drove it to our nearby tire shop to have the brakes inspected, the oil changed and fresh tires put on. All things done and very reasonable. We even upgraded the out of round steel wheels to some slick aluminum Vision brand rims. Pride abounded. We drive it out of the parking lot and ALL the dash lights come on!!! I drive down the hwy and circle back. The shop brings out their handheld code reader. They are a tire shop, not a mechanic. They tell me it is code P0455 - EVAP system, gas cap leak. He says when these trigger, that the entire Toyota computer freaks out and lights up the dash. We are taking the tire pressure light comes on and stays on, the Traction Control light, the check engine light, the ABS light and I am probably forgetting something. It looks like a Christmas tree! Ok, I say to the guy. No big deal. I will drive up to Toyota and purchase an over priced factory gas cap, for my new baby. And while I am there, I will pay them way too much money to scan the vehicle for codes as well. Just to be sure. Well, Toyota dealership tells me same thing. It is just an EVAP gas cap thing. But they don't understand why replacing the gas cap and clearing the code didn't clear the code. So they tell me $3000-4000 to replace the entire EVAP system and check for leaks and this may not fix things. Obviously they don't want to repair a vehicle this old. I can take a hint. I tell them to have a nice day and take it to my local auto parts store to find out the nearest retired Toyota mechanic in our area. Take the vehicle to him. He keeps it for a week. Tells me he can't find the leak, it is driving perfectly fine but take it to this guy so and so to be sure. I take it to that guy. He has the vehicle for 2 weeks. Put in a new EVAP system for me. The code to won't clear and the lights won't stay off. He says he has run out of answers. I take it another shop, performance guys who claim they love to work on Japanese cars; they tell me for $200 they will run a smoke machine and diagnose it. I tell them let's wait. $200 seemed a little high to me if the vehicle has no actual drive-ability or safety issues and we have already spent a chunk hunting a wild goose. Talk to some mechanics working at a different parts store about the mystery. They suggest I check hoses. I research how this EVAP system works and I do what I can from the engine and sure enough, I find a completely cracked vac hose going the fuel system and replace it myself for $1.45. Was shocked none of these other certified bone heads saw it! Get the code cleared, drive it on the hwy, run good fuel through the system for several miles and feeling good. Lights stayed off for exactly 2 days of driving. You can imagine my dismay when it came back on and has stayed on since. I don't know much about this type of thing but it seems like it should be a simple fix. Or maybe not. Btw, not a darn thing wrong with the wheels or the TPMS system that 3 tires shops could find. Not even with the spare wheel/tire. The tire light never flashes. It just comes on and stays on in time with the other lights every time you crank the vehicle.

The Highlander is having only one other hopefully minor issue which I am unsure if it is related or not to the code. It was idling a little rough at stop lights and occasionally sort of pulls itself forward as you slow down. It doesn't do it all the time so the first thing I did was 'reset' the idle as it stayed around 1400 rpm after cold start and run name brand fuel system cleaner. It no longer does the high rev at cold start but still occasionally idles rough and pulls forward. It isn't severe enough to cause any safety issues that we can observe and not sure if this is a normal vintage Toyota thing or not. We are fairly new to such a small engine and totally new to Japanese engineering. And that issue may not be related in any way to the EVAP mystery. But thought I would mention it.

I know most of you drive or prefer the Highlander Limited with the V6 as most posts are about that model, but I have to tell you, this vehicle is a pleasure to drive. It is plenty peppy in traffic, very comfortable for 4 people to travel on long trips and gets incredible gas mileage for being so spacious and high off the ground. We truly like our first Toyota (and wished Scotty would have featured it in his recent best SUV to purchase video because it is near showroom condition for being so old!) but we would love it even more if we could solve the mystery. It gets old telling passengers to trust us the vehicle is safe to drive/ride despite all the lights on. lol! Thanks in advance for reading this lengthy post and for your replies.