weird shaking...thoughts?

[mendozer]

The other week we were driving on forest roads for a hike. We came down, stopped in town for something then hopped back in. I noticed the whole rig was shaking after starting the car and it continued to shake when backing out of the stall. Unsure what happened, I turned it off then on again, still shook. I drove down the road a bit to grab lunch and turned the car off. After that it was fine.

Couple days later same thing happened. Turned on after driving for a bit then turned off (this is important, it has never done it on a cold start). I was on the freeway at the time. Pulled over and looked under the hood, nothing looked weird. Hopped back on and drove. it drives kind of rough and the whole car just vibrates more. Then it throws a code P0304, misfire of cylinder 4. After driving for a while it tends to smoothen out and again overnight it fires up. These are the thoughts I had:

1. fuel injector (can get clogged, they were fully disassembled and rebuilt at 178k (now at 232)

2. spark plugs. I'm only 35k in from the last change, using the iridium ones rated for 60k intervals. plus I'd imagine cold starts would be more prevalent for spark plugs.

3. engine mount. The forest road was SUPER bumpy on the way down and I was shaking the whole damned car. My shocks are old and don't absorb these things well anymore. Maybe a mount got damaged....but then again that would be more consistent.

Happens when hot, resting, then start up again. My brain says fuel injectors. I did two concentrated fuel system additive treatments and I bought spark plugs just in case...but anything sounding like anything else?

 

[thennen]

The other week we were driving on forest roads for a hike. We came down, stopped in town for something then hopped back in. I noticed the whole rig was shaking after starting the car and it continued to shake when backing out of the stall. Unsure what happened, I turned it off then on again, still shook. I drove down the road a bit to grab lunch and turned the car off. After that it was fine.

Couple days later same thing happened. Turned on after driving for a bit then turned off (this is important, it has never done it on a cold start). I was on the freeway at the time. Pulled over and looked under the hood, nothing looked weird. Hopped back on and drove. it drives kind of rough and the whole car just vibrates more. Then it throws a code P0304, misfire of cylinder 4. After driving for a while it tends to smoothen out and again overnight it fires up. These are the thoughts I had:

1. fuel injector (can get clogged, they were fully disassembled and rebuilt at 178k (now at 232)

2. spark plugs. I'm only 35k in from the last change, using the iridium ones rated for 60k intervals. plus I'd imagine cold starts would be more prevalent for spark plugs.

3. engine mount. The forest road was SUPER bumpy on the way down and I was shaking the whole damned car. My shocks are old and don't absorb these things well anymore. Maybe a mount got damaged....but then again that would be more consistent.

Happens when hot, resting, then start up again. My brain says fuel injectors. I did two concentrated fuel system additive treatments and I bought spark plugs just in case...but anything sounding like anything else?

Try swapping coil packs to see if it follows? Or even easier, when it's idling rough, disconnect that coil pack and see if it changes.

 

[mendozer]

i thought about the pack because of all the vigorous shaking. I can't disconnect it while running just due to space of my hands/tools. I'll swap it today and see if it follows.

 

[2TH4IST]

You have a v6 correct?

Firstly, get the dual electrode spark plugs in there (NGK 3967) if its a v6. Next I would swap the coils to see if the misfire follows a single coil pack. If it does, your coil is toast, replace it. If it doesn't, it could be the injectors. You can run some bg44k injector cleaner. Run your tank low, then dump the bg44k into the tank right before you fill up so the fuel mixes the cleaner well. Drive the tank, and see if any improvements happen. If not then it might be your injectors. I'd recommend motor west's updated injectors, again if it's v6.

Enhance Performance and Reliability with 5VZ-FE Fuel Injectors | MotorWest Performance

 

[mendozer]

yes its a 3.4 V6. I always get the dual ones, even though the FSM says otherwise.

Is there harm in doing too much additive? Other than not knowing what the fix was. I did Lucas Oil fuel injector then a Chevron one (i forgot I bought a pack from Costco a while back)

 

[mendozer]

Interesting bit from MW's page:

"After extensive research and development, we are discontinuing this product and introducing a more reliable and cost-effective (compared to new) Denso injector replacement.

The original 23250-62040 (brown) injectors have a known internal solenoid defect that leads to failure over time, particularly in high-mileage engines.

Symptoms typically start with intermittent random misfires, which become more consistent as the engine reaches normal operating temperature.

Eventually, the internal injector solenoid fails completely, causing a permanent misfire.

We’re excited to offer a lasting solution that is covered by a lifetime warranty for your peace of mind"

that describes this scenario once warmed....

 

[Endlessblockades]

Interesting bit from MW's page:

"After extensive research and development, we are discontinuing this product and introducing a more reliable and cost-effective (compared to new) Denso injector replacement.

The original 23250-62040 (brown) injectors have a known internal solenoid defect that leads to failure over time, particularly in high-mileage engines.

Symptoms typically start with intermittent random misfires, which become more consistent as the engine reaches normal operating temperature.

Eventually, the internal injector solenoid fails completely, causing a permanent misfire.

We’re excited to offer a lasting solution that is covered by a lifetime warranty for your peace of mind"

that describes this scenario once warmed....

Whew I was afraid the blurb applied to the MW injector set I bought in April. Apparently not.

 

[mendozer]

i swapped coil packs 2/4 and while doing so i pulled the plug of #4 just to see. and the gap was well over .50. i crimped it back down. But I also noticed it was K16TR11. On my order from amazon last year they were supposed to be the iridium version PK16TR11. So I'm definitely at or over the 30k interval for these. I was expecting them to be 60k.

So maybe it's simply that? Either way I'll see what happens. It shook on me today again but dissipated as I kept driving. I have new plugs coming in a day or two, the real Iridium ones.

 

[2TH4IST]

Hmm be careful buying spark plugs on Amazon. There has been reports of fake spark plugs. I'd recommend rockauto or a physical parts store. I know the iridiums sound good but our 5vz's need the dual electrode ngk spark plug.

 

[mendozer]

the ones i ordered directly from Denso were the double grounded iridium ones. I know that technically they won't last truly as long as iridium bc of the wasted spark design, but it will still be longer than 30k. I don't mind the few extra bucks

 

[phattyduck]

the ones i ordered directly from Denso were the double grounded iridium ones. I know that technically they won't last truly as long as iridium bc of the wasted spark design, but it will still be longer than 30k. I don't mind the few extra bucks

The problem is Amazon, not the parts you ordered. Basically all NGK and Denso plugs on Amazon are fake. Get quality parts from your local parts store or RockAuto (or other actually reputable online vendor).

-Charlie

 

[thennen]

i swapped coil packs 2/4 and while doing so i pulled the plug of #4 just to see. and the gap was well over .50. i crimped it back down. But I also noticed it was K16TR11. On my order from amazon last year they were supposed to be the iridium version PK16TR11. So I'm definitely at or over the 30k interval for these. I was expecting them to be 60k.

So maybe it's simply that? Either way I'll see what happens. It shook on me today again but dissipated as I kept driving. I have new plugs coming in a day or two, the real Iridium ones.

After swapping coil packs 2/4, were you able to check to see if the problem followed? I know it shook again, as one would expect. But same cylinder?

 

[Hungryhawk]

Misfire, shaking

I too think the ignition , perhaps plugs or defective plug cable?
Misfire can ruin your cat converters. Do your O2 sensors show anything amiss?

 

[mendozer]

The problem is Amazon, not the parts you ordered. Basically all NGK and Denso plugs on Amazon are fake. Get quality parts from your local parts store or RockAuto (or other actually reputable online vendor).

-Charlie

I buy them usually from the Denso store and they come in the boxes and they're labeled properly. Unless they're getting really good at fakes

 

[mendozer]

After swapping coil packs 2/4, were you able to check to see if the problem followed? I know it shook again, as one would expect. But same cylinder?

hasn't happened again yet. haven't driven today. I'l running errands tomorrow so maybe a chance there. Maybe squishing the plug tighter helped? i have my new plugs in the mailbox outside. I might put them in on monday

 

[mendozer]

ok so plugs are in and coils swapped. It shook yesterday leaving a store and I was hoping for a code as it was getting stronger waiting at a red light, then it just kind of worked itself out. Stupid reliable toyotas! Give me a code!

I'm thinking if it gives me P0302 it's the coil pack (bc that was on cyl 4 before).

If it gives me P0304 then it's the fuel injector bc of the solenoid issue mentioned above.

Is that sound logic?

 

[mendozer]

p0304 came on today. Also unlike before where it resolved, the shaking got stronger at 50 mph. so I'm assuming it truly is the fuel injectors.

 

[Hungryhawk]

Any evidence of rodents hanging out under hood?
Their chewing on wiring can cause lots of electrical issues with the easy access and delicate ignition system.

 

[phattyduck]

Any evidence of rodents hanging out under hood?
Their chewing on wiring can cause lots of electrical issues with the easy access and delicate ignition system.

This generation is pre soy-based insulation on the wires, so this is less likely... but not totally out of the realm of possibilities.

-Charlie

 

[mendozer]

no evidence of that no. I'm awaiting new injectors from MWP. I did pour another bottle of fuel injector cleaner at my fillup yesterday. I stopped three times today during errands and it was ok starting up.

Also...soy wires? wtf this damn soy is everywhere