Help Deciphering Misfire Diagnosis

My 2001 was misfiring so I took it in for a diagnosis. It seemed like it was running fine, but I semi recently bought and haven't driven due to chasing electrical drains and fixing valve cover leak.

The mechanic report is below. They recommended rebuilt/reman head or engine replacement. I'm not knowledgeable enough to know if they're other possibilities. Thanks in advance for anyone that could provide some insight.


Technician's Notes: P0300 random misfire, P0301 P0303 P0305, Cylinder 1 3 5 misfire. Vehicle barely runs, has spark and fuel on the affected cylinders. Checked cam timing since the misfires are confined to one bank, cam timing is good. Removed the spark plugs and found two wet with fuel and one fuel fouled. Did a compression test and found zero compression from cylinders 3 and 5. Leak down test indicated a problem with the intake valves. Removed the valve cover to inspect for valvetrain damage, everything looks good, next step would be to remove the cylinder head to inspect for a bent valves or valve seat issues.

 

Could perform a cylinder leak down before pulling the head to get a little more insight before such a large project.

 

They did the above. Or is there a different test you are referring to?

 

You are correct, I missed seeing that. My bad.

 

Yeah, that leak down and compression test sounds bad. Either a new head or a whole new engine. I'd let him pull the head and get a final verification and then go from there.

 

Thank you for the response. The prices they gave me to replace head or engine were pretty cost prohibitive.

but I didn't come across the below post where it was suggested, for a vehicle with similar problems, could be just fuel injection related? Or is my inspection result worse and more of a nail in the coffin? The engine was running fine until I accidentally ran it out of gas while working on other problems.

 

Nothing like that is going to fix zero compression in those cylinders.

 

Well crap. Was being hopeful.

 

What changed after you dropped it off? A 6 cylinder engine with two cylinders having zero compression will not seem like it's running fine. The check engine light will flash and it will run like shit. It likely also won't be intermittent. The mechanic said it barely ran...
Other thoughts-
No mention of checking valve clearance? Additionally, intake valves rarely cause problems on Toyotas. Not saying its impossible, but I would get a second opinion.

 

The mechanic said in their shops experience, replacing heads can be a 50/50 outcome in similar situations (has 205k miles and not sure if there's other problems).

 

The problem started after I ran it out of gas while running it in my driveway to find an electrical problem. I had only driven it during a test drive, which seemed fine to my untrained eyes/ears. After it ran out of gas, the misfire issue started up.

I spoke to another mechanic and described the inspection report and he said he wouldn't touch it, not worth the trouble for 'him or me'.

 

Wow, really? It sounds like you need to find someone who likes to work on Toyotas! Where do you live?

 

It was a two mechanic shop, so maybe that played into it. I'm outside of Vancouver, Wa.

The shop that diagnosed it said remanned heads would be $5k, which is probably slightly less than the vehicle would be worth if it was running.

 

There's always the tiny chance the mechanic didn't do a proper compression test. I think you can rent a compression tester at Autozone and just verify yourself. Or like CygnusX-14 said...try for a second opinion.

 

Found a place in Portland that is allegedly a reputable (per Reddit) Japanese focused (per their website) mechanic. Hoping they can give me a price for worse case scenario (replaced heads) and then tow it over there for a 2nd opinion.

 

Any chance I idioted up my valve gasket replacement and that's causing the misfire?
The shop that originally diagnosed the problem didn't think so since the leak down test indicated a valve problem.

 

I would think then you'd have exhaust in the coolant and overheating.

 

only run it for a couple seconds so not sure if that's enough time for that to arise?

 

Get a 2nd opinion. The coolant exhaust gas tester might be a good investment.

Unfortunately it is not unheard of for 5vz with >250k miles to crack the head, but I'd be surprised