Did you maybe torque them with anti-seize? I believe the book torque is for dry.
Intermittent stumble/miss/misfire on 2000 LC - no codes
- Thread starter re_guderian
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
I am working through these items right now so thanks for posting the write up..
re_guderian
SILVER Star
- Thread starter
- #23
Probably. I'm trying to remember,I "think" they came with the copper stuff. But I was also having the issue before I swapped out all 8.
Old thread, but worth reviving......
Have been experiencing the EXACT same symptoms, and when I went and checked the recently-changed-by-the-PO plugs, several of them were way looser than they should be. When I tightened them properly......nothing. Same issues. Random misfire (seems to only be from cold to nearly operating temperature), but it is pronounced. Once warm, no more misfires.
Wonder if I ought to just go in and replace all of the plugs and coil packs with new? I hate to do that with no stored codes, but I'm sort of at a loss with no solution from the exact same running conditions.
Any thoughts from anyone?
Have been experiencing the EXACT same symptoms, and when I went and checked the recently-changed-by-the-PO plugs, several of them were way looser than they should be. When I tightened them properly......nothing. Same issues. Random misfire (seems to only be from cold to nearly operating temperature), but it is pronounced. Once warm, no more misfires.
Wonder if I ought to just go in and replace all of the plugs and coil packs with new? I hate to do that with no stored codes, but I'm sort of at a loss with no solution from the exact same running conditions.
Any thoughts from anyone?
Torquing spark plugs always gives me the willy's. I Really Don't Want to spin one of those things.
I'm also experiencing the same issues as the OP and @dnp. 
Shows up after cold start until it warms up. Will shock/pulse the brake pedal harshly when depressed and the RPM's will thud/drop for a split second but nothing noticed while the truck is moving. Here's what I tried so far... but problem persists 
cyl 8 (New Plug / New Coil) cyl 7 (New Plug / Old Coil)
cyl 6 (New Plug / Old Coil) cyl 5 (New Plug / New Coil)
cyl 4 (New Plug / Old Coil) cyl 3 (New Plug / Old Coil)
cyl 2 (New Plug / New Coil) cyl 1 (New Plug / Old Coil)
Replaced cyl 2 coil with new because it threw a code at me
problem still persists.........
Checked all vacuum lines, they're old as dirt and a little cracked on the ends. Thought about ordering throttle body gasket and trying some throttle body cleaner along with a fuel system cleaner and see where it takes me. Might even snag some injectors from RockAuto if available and see if that helps. Have a bad feeling it's probably something more complicated. Still reliably gets my wife to and from work, so there's that.
Shows up after cold start until it warms up. Will shock/pulse the brake pedal harshly when depressed and the RPM's will thud/drop for a split second but nothing noticed while the truck is moving. Here's what I tried so far... but problem persists cyl 8 (New Plug / New Coil) cyl 7 (New Plug / Old Coil)
cyl 6 (New Plug / Old Coil) cyl 5 (New Plug / New Coil)
cyl 4 (New Plug / Old Coil) cyl 3 (New Plug / Old Coil)
cyl 2 (New Plug / New Coil) cyl 1 (New Plug / Old Coil)
Replaced cyl 2 coil with new because it threw a code at me
problem still persists.........Checked all vacuum lines, they're old as dirt and a little cracked on the ends. Thought about ordering throttle body gasket and trying some throttle body cleaner along with a fuel system cleaner and see where it takes me. Might even snag some injectors from RockAuto if available and see if that helps. Have a bad feeling it's probably something more complicated. Still reliably gets my wife to and from work, so there's that.
Last edited:
Follow-up...
I think I found the problem to my miss/hiccup/stumble... Denso part # 101362-1820 or #25860-50100... "Vacuum Valve Assembly" (VVA) or could be referred to as "Vapor Canister Purge Solenoid" (VCPS)... see below photo
The short rubber hose connecting the top of the intake manifold to this VVA was completely dry rotted and... at some point between 1 mile and 255k miles... snapped off the plastic stem of the VVA. (See below photo)
So, I figured this could be the cause of my miss/hiccup/stumble since nothing else seemed to be out of sorts, that I know of. I decided to duct tape the two places where the dry rotted hose connected to the VVA and the top of the manifold and VOILA... no more miss/hiccup/stumble. Now to find the cheapest dealer of the part.. RockAuto carries but is $115.99 and then you have to pay shipping.. Amazon seems to have it for $77~.. Gotta have it I guess haha
Here's another hose connecting the VVA to the Fuel Evaporation Canister. It's a bit dry and tough so I might replace this while I'm at it. Anyone know what this little box is? And, how often should the Fuel Evap Canister be replaced/cleaned out, if ever?
Hopefully, this helps anyone who's dealing with the same issues regarding the 2UZ-FE.
I think I found the problem to my miss/hiccup/stumble... Denso part # 101362-1820 or #25860-50100... "Vacuum Valve Assembly" (VVA) or could be referred to as "Vapor Canister Purge Solenoid" (VCPS)... see below photo
The short rubber hose connecting the top of the intake manifold to this VVA was completely dry rotted and... at some point between 1 mile and 255k miles... snapped off the plastic stem of the VVA. (See below photo)
So, I figured this could be the cause of my miss/hiccup/stumble since nothing else seemed to be out of sorts, that I know of. I decided to duct tape the two places where the dry rotted hose connected to the VVA and the top of the manifold and VOILA... no more miss/hiccup/stumble. Now to find the cheapest dealer of the part.. RockAuto carries but is $115.99 and then you have to pay shipping.. Amazon seems to have it for $77~.. Gotta have it I guess haha
Here's another hose connecting the VVA to the Fuel Evaporation Canister. It's a bit dry and tough so I might replace this while I'm at it. Anyone know what this little box is? And, how often should the Fuel Evap Canister be replaced/cleaned out, if ever?
Hopefully, this helps anyone who's dealing with the same issues regarding the 2UZ-FE.
Edit: The part on RockAuto, found under the Lexus section is $115.99 but under the Toyota section is listed for $34.79... Toyota it is!
As of yesterday, the hiccup is back. Maybe it's because I keep thinking about it ... isn't that how hiccups work?
Plugging in four brand new coils tonight and ordering more parts and vacuum lines. Lordy
Plugging in four brand new coils tonight and ordering more parts and vacuum lines. Lordy
Sorry I keep showing up here and posting my progress but I'm trying to track my work a little and am hoping to help someone experiencing the same issue as me.
To recap, cyl 1,2,3,4, and 6 all got new spark plugs a few weeks ago. Last summer, cyl 5 and 8 got new spark plugs AND coils. So, last night I swapped out cyl 2,4, and 6 with new coils and cyl 7 got a new spark plug AND coil (cyl 7 was a b****). So, I only need two more coils to finish the job. Side note: Before installing the new coils on 2,4, and 6, I checked the tightness of each plug, they weren't loose but definitely not as tight as I had them before. Each were retightened. I also noticed most of the vacuum lines had cracks in the ends so I duct taped those to further diagnose the issue, definitely not good practice but I'm trying to rule things out.
After last night's swap-out and tape-up, the truck fired up with more energy and ran smoother with almost zero hiccup/miss issues. There was a very very minutely noticeable bump/vibration that didn't seem to be in-time with the engine. It seemed to have this little bump/vibe before the miss/hiccup issues, not sure what could be causing this. Starting to wonder if it's the cat's ? There also didn't seem to be any issues this morning during the 10 minute drive to work with the hammer down. We'll see how it goes after work.
Ordering 2 coils, TPS, Vapor Canister Purge Valve, Air filter, Fuel Filter and vacuum lines.
To recap, cyl 1,2,3,4, and 6 all got new spark plugs a few weeks ago. Last summer, cyl 5 and 8 got new spark plugs AND coils. So, last night I swapped out cyl 2,4, and 6 with new coils and cyl 7 got a new spark plug AND coil (cyl 7 was a b****). So, I only need two more coils to finish the job. Side note: Before installing the new coils on 2,4, and 6, I checked the tightness of each plug, they weren't loose but definitely not as tight as I had them before. Each were retightened. I also noticed most of the vacuum lines had cracks in the ends so I duct taped those to further diagnose the issue, definitely not good practice but I'm trying to rule things out.
After last night's swap-out and tape-up, the truck fired up with more energy and ran smoother with almost zero hiccup/miss issues. There was a very very minutely noticeable bump/vibration that didn't seem to be in-time with the engine. It seemed to have this little bump/vibe before the miss/hiccup issues, not sure what could be causing this. Starting to wonder if it's the cat's
? There also didn't seem to be any issues this morning during the 10 minute drive to work with the hammer down. We'll see how it goes after work.Ordering 2 coils, TPS, Vapor Canister Purge Valve, Air filter, Fuel Filter and vacuum lines.
How difficult is it to replace the throttle position sensor?
Not too difficult, the three screws holding it on were really tight on mine. Once they’re out, super simple.
And believe it or not, my local Toyota dealer had the part cheaper than I could find an off brand at NAPA.
Where I got mine:
And believe it or not, my local Toyota dealer had the part cheaper than I could find an off brand at NAPA.
Where I got mine:
Toyota Parts and Accessories Online - Fred Anderson Toyota in Raleigh, NC
Buy genuine Toyota Parts and Accessories online from Fred Anderson Toyota. Trust Toyota OEM Parts to get back on the road fast. Shipped fast from Raleigh, NC.
parts.fredandersontoyota.com
