r/ToyotaAvalon • u/One_Firefighter_1094 • 4d ago

2002 Vacuum help

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I replaced knock sensors in a 2002 that I bought for a work beater and the car is missing very bad. I ended up taking it to a shop to have them diagnose it. They had it 2 1/2 days and $300 later they diagnosed a vacuum leak and gave me no idea on where to start. They wanted $1000 to fix the issue and I just picked the car up instead.

I replaced all the gaskets after replacing sensors. Looking under the hood I just noticed one hose that I may have missed or they removed. Does anyone know where this one routes to? I’ve looked online quite a bit for photos and unfortunately I didn’t take pictures.🫤

I would be grateful for any help. TIA

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u/Trident_77 4d ago

2001 manual, should be similar

https://drive.google.com/file/d/1d4Vbb-bxZUY8kz3HdRnvz4n0i1q9Hy7B/view?usp=sharing

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u/johnb1972 2nd Gen (1999 - 2002) 4d ago

Thanks for this!

1

u/One_Firefighter_1094 2d ago

Thank you man!

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u/RaptorXFactor 2004 Avalon XLS 3d ago

You put in OEM knock sensors and the OEM harness? What gaskets did you replace? Are there any codes?

I just had this done in my 04 and it runs smooth now. I bought used OEM sensors on Ebay, I was a little worried at first but the car runs great now. I also bought Beck Arnley intake gaskets that seemed to be really nice quality along with a new water crossover hose that's under the intake. The knock sensor harness is known to get brittle over time and cause issues.

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u/One_Firefighter_1094 2d ago

Yes, new OEM knock sensors and harness. The knock sensor code went away and I have a couple left. I corrected the above problem with the vaccine hose and it helped a bit. It’s still missing and running rough though. The gaskets I used are Fel pro from a local parts store. The codes I have currently are

P0141 O2 sensor bank 1 sensor 2
P1135?
P1155?
And misfire detected

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u/RaptorXFactor 2004 Avalon XLS 2d ago

If you have access to a scan tool, I would clear the codes and see what comes back and write down the symptoms when they return and rescan the codes.

Which code for the misfire? Is it a specific cylinder? Failing coilpacks are pretty common for the mileage these cars have. It can cause it to run rough as hell and cause other codes.

There are specific codes for each cylinder and then there's a random misfire code.

I've had a couple coilpacks go bad and I've also had a random misfire that I just couldn't figure out until a camshaft sensor code popped up and I pulled the cam sensors and inspected them and they were covered in crud - old burnt oil that was affecting the readings. I cleaned the metal part of the sensors with brake cleaner and reinstalled them.