3.4L V6 99 Tacoma - "Misfire", Clicking Noise, No CEL

Hi all,

My problem feels like a misfire, but with a metallic clicking noise and no CEL (drove with issue for 4 miles/20 minutes).

Background:
- New spark plugs (dual electrode) and cables about 15k miles ago.
- Diaelectric grease added with new plugs
- Fuel Injector misfire and replacement (8k miles ago - easy CEL)
- 158k miles

Problem details:
- Noticeable clicking sound started 6k miles ago (september 2019)
- Three days ago, the clicking got louder from driving home at 75-80 mph.
- While in streets yesterday, symptoms mentioned began and were consistent. Power cycling the truck didn't get rid of the problem.
- Issues happen when engine is cold and hot
- Symptoms occur when in idle (parked or braked), driving, neutral, etc
- No CEL

Current plan for Sunday morning:
- Inspect all spark plugs
- Clean and apply new dielectric grease
- Test resistance of spark plug cables and coils
- Inspect fuel injectors

Please refer to the videos.

 

That is definitely running rough. You had to disconnect a lot of hoses to get to the injectors. Have you checked for vacuum leaks?

 

Yeah, I think you're suggesting the most feasible thing. I listened to the video as well and something is amiss.

OP, you're plan to go back in sounds good. As Kiloyard says I'd be double checking all vacuum piping and connections. Maybe double check spark plugs hasn't come a little loose on ya. I've run into slightly similar symptoms with that being the cause.

There will be some guys here with vastly more experience with the 5VZ that will likely know better off the sound in the vid.

 

there should be a "pending" code stored in the PCM. If you have a scan tool check that first. Hopefully this will give you an indication of the problem cylinder... as an example, a P0305 is misfire cylinder 5, a P0300 is a random misfire all cylinders. If it is a single cylinder then a compression test should be preformed to verify. We are trying to figure out is it a mecahical issue... bad valve, bad cam etc or is it external, fuel, spark etc.

I listened to the audio portion of the video and it is tought to tell at least for me without being right there. If you take a long screw driver, a piece of EMT, a rubber hose... pretty much anything metallic that will transmit sound and put it on the valve cover then put your ear to it and listen then move it around you can localize the noise pretty good.

When was the last time the valve clearances were checked/adjusted?

 

Hi guys,

Appreciate the time to provide some knowledge.

I want to clarify something to readily apparent in the video: sounds like something came loose and is rattling in there. It is cyclical and the rattles per second increases with increasing RPMs.

I currently leaning towards holding off on the debugging for a day or two; figured that buying the the compression tool, etc would making the debugging most time effective.

kiloyard, I’ll inspect the vacuum hoses. Cruiser guy, I’ll look at the spark plugs.

glamisman, there was a misfire in 5 pending code that I assumed was from the previous issue (misfire in cylinder 5 solved by changing the fuel injector). I ended up clearing it to see if it would come back.

I like the tool idea. I was planning on buying a stethoscope; do you recommend the custom tool instead?

on the valve clearances: has never been checked.

Hopefully checking all the low hanging fruits and completing a compression test will give a good direction.