'17 Tacoma - Misfire Cylinder 5, System Too Rich Bank 1 (HELP)

Truck started bogging down at stop light. Trac & Engine light came on. Detected cylinder misfires on 1,3,5. Changed spark plugs and got only a misfire on cylinder 5. Cylinder 5 plug was wet with fuel. After that I took it to the dealer where they inspected wires, coils. They performed a leak down test on cylinders 3 (174 psi) & cylinder 5 (170 psi). They told me it was the fuel injectors, so when they went to swap injectors, they noticed cylinder 5 had an intake valve leak. They wanted to charge me around $7,000 to send to machine shop to get fixed. I took my vehicle and ran. Is this a fishy diagnosis? And does anybody have other ideas on what it could possibly be? Thanks.

 

Likely not fishy, but they were certainly throwing parts at it.

Unfortunately, a few Tacos have had valve seat issues in Cylinder 5. It should be fixed if still in the powertrain warranty, but I would think that you are past that now.

 

How many miles?

 

69k miles

 

What year and build date?

 

2017. October 2017

 

Intake valve leak should have shown up on the leak down test.
That test is done with piston at TDC on the power stroke and all the valves closed

 

And 170 psi of compression ? It's one or the other. If it leaks down after 20 minutes, big whoop. it only needs to hold pressure for a few ms.

Run a couple of cans of Seafoam or techron ect. Maybe there's a bit of carbon on the valve seat.

 

Update: Took it to a hometown mechanic and it ended up being the direct fuel injectors (internal) on bank 1.
No intake valve leak.

 

What percentage leakdown does it have?..we see some direct injections with carbon under the valves