Engine sputtering after plug change RX400h
Pit Crew
Joined: Jul 2014
Posts: 204
Likes: 36
From: il
Thank you for the pics. I always find the arrows and notes very helpful. 
Does anyone know why the some of coil packs go bad during install? I think I can across several post somewhere where the packs went bad during the spark plug change. One would think if it was fine before it would be fine after. I can see it can be a pain in the behind especially if you have to wait for parts online.
Does anyone know why the some of coil packs go bad during install? I think I can across several post somewhere where the packs went bad during the spark plug change. One would think if it was fine before it would be fine after. I can see it can be a pain in the behind especially if you have to wait for parts online.
Thread Starter
Pole Position
Joined: Apr 2016
Posts: 234
Likes: 26
From: CO
I don't know why either but it sure seems odd to me as well. They've worked for 150k....why now to go out because I disconnected and re-connected?!?
And they are not cheap! Have to do Amazon or similar to keep costs down.
And they are not cheap! Have to do Amazon or similar to keep costs down.
Driver School Candidate
Joined: Dec 2017
Posts: 8
Likes: 0
From: IL
If I buy an RX400h this weekend, it will need timing belt and spark plugs replaced. Will have my mechanic do timing belt (he's great with hybrids). Will spark plugs take much more time while he's in there, or are these two different beasts?
Thread Starter
Pole Position
Joined: Apr 2016
Posts: 234
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From: CO
Agreed. The plugs on on the top side and the timing belt is on the side. Only minor things are related such as plastic covers, air box, etc. Not a lot of overlap unfortunately.
But both are big labor jobs. Maybe you could talk them into a reduced price if you did both at the same time?!?
You'll need to change your water pump and pulleys at the same time as the timing belt. Kinda like, "might as well while we're in there" thing.
But both are big labor jobs. Maybe you could talk them into a reduced price if you did both at the same time?!?
You'll need to change your water pump and pulleys at the same time as the timing belt. Kinda like, "might as well while we're in there" thing.
Driver School Candidate
Joined: Dec 2017
Posts: 8
Likes: 0
From: IL
Agreed. The plugs on on the top side and the timing belt is on the side. Only minor things are related such as plastic covers, air box, etc. Not a lot of overlap unfortunately.
But both are big labor jobs. Maybe you could talk them into a reduced price if you did both at the same time?!?
You'll need to change your water pump and pulleys at the same time as the timing belt. Kinda like, "might as well while we're in I spoke with my mechanic. With spark plug change and timing belt, closer to $900. Not liking as good of a deal.
Thanks for all of your input. I’ll be sure to check back in case anyone else chimes in. " thing.
But both are big labor jobs. Maybe you could talk them into a reduced price if you did both at the same time?!?
You'll need to change your water pump and pulleys at the same time as the timing belt. Kinda like, "might as well while we're in I spoke with my mechanic. With spark plug change and timing belt, closer to $900. Not liking as good of a deal.
Thanks for all of your input. I’ll be sure to check back in case anyone else chimes in. " thing.
The vehicle is only $3700. Spark plugs were never changed.
$900 in maintenance, $700 body work and $400 in tires = $5700 for a 2006 rx400h with 206k miles.
Have to decide in the morning. Any input is greatly appreciated!
Thread Starter
Pole Position
Joined: Apr 2016
Posts: 234
Likes: 26
From: CO
I suppose it depends on your skill level. You could always try and do the plugs yourself and save a little.
If $900 is the combined parts and labor price for both, that's not too bad really. I am thinking I got around $900 quote for just the timing belt. Be sure that includes a new water pump and pulleys. At that mileage, you really should change that out too.
Still, $5700 isn't a bad investment for a solid vehicle. I sold ours with 175k for around $9500, new tires, brakes, bearings, front axle shafts, etc. Really in good shape. Guy saw it, drove it, and didn't dicker. He knew it was in great shape for that price. Just a data point for you.....
If $900 is the combined parts and labor price for both, that's not too bad really. I am thinking I got around $900 quote for just the timing belt. Be sure that includes a new water pump and pulleys. At that mileage, you really should change that out too.
Still, $5700 isn't a bad investment for a solid vehicle. I sold ours with 175k for around $9500, new tires, brakes, bearings, front axle shafts, etc. Really in good shape. Guy saw it, drove it, and didn't dicker. He knew it was in great shape for that price. Just a data point for you.....
Thread Starter
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Joined: Apr 2016
Posts: 234
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From: CO
Advanced
Joined: Jan 2017
Posts: 556
Likes: 48
From: Quebec
Thanks for that. Just spoke with my mechanic again. With spark plug change and timing belt, closer to $900.
The vehicle is only $3700. Spark plugs were never changed.
$900 in maintenance, $700 body work and $400 in tires = $5700 for a 2006 rx400h with 206k miles.
Have to decide in the morning. Any input is greatly appreciated!
The vehicle is only $3700. Spark plugs were never changed.
$900 in maintenance, $700 body work and $400 in tires = $5700 for a 2006 rx400h with 206k miles.
Have to decide in the morning. Any input is greatly appreciated!
I found a receipt in the vehicle indicating the spark plugs were changed although the timing belt was unknown....
I started with that, fortunately I had a friend mechanic changed the timing belt & related parts at a extremely reasonable cost, I brought the parts, my total cost was around $275.
unfortunately when there are indications that some maintenance was ignored, you can bet some other things will pop up eventually.
Later, I needed rear shocks, parking brake repaired, front shoes, AFS light sensor, winter tires with rims & a few other minor things.
After a year my total is around $4,500., best investment on a vehicle to date as now the RX is a joy to drive.
My RX had 137K, at 200K plus I would try to offer less for the vehicle.
Driver School Candidate
Joined: Aug 2019
Posts: 1
Likes: 0
From: Norfolk
Igot these spark plugs:
Denso (3297) SK20R11 IridiumSpark Plug
Got them on Amazon for $6.30 ea. You can also pick them up at Advance Auto but more expensive. You may even check out your local Toyota and Lexus Dealer.
As far as instructions, I basically just went for it. I did look at a few "other type of lexus cars" but some of them actually had more stuff to do. There really is only 3 hoses that you need to disconnect, and they are all at the Throttle Body. Two are coolant ones and the shape pretty well defines where each one goes. The other is maybe the crank case vent...something without liquid.
My recommendation, Definitely get some ratcheting type wrenches. I had them already and love them. IF you don't have them, go get some. There are 3 rear bolts that would be pretty difficult to remove otherwise. But pretty easy with a ratcheting wrench.
Because I just joined the forum, I can't post pictures for 30days. So can't really do a play by play for you.
I did not replace any of the rubber gaskets as some other threads pointed out. Mine seem to be in decent shape. I also didn't do the PCV valve.
Some note worthy key things I can recall.
After removing the throttle body unit (where the electrical connector and 3 hoses plug into), there is a 12MM bolt on right side that holds the intermediate metal intake between the TBI unit and the plastic intake. Then the surrounding bolts and nut to remove from plastic intake.
Two bolts on back side of plastic intake. The one on right side (after metal intake is removed), is a 12MM. The other one is on left side and is a 14MM (I believe).
Once all the intake bolts are removed, and the two nuts....there will be two star studs still holding the plastic intake in place. I used like a 7/32 socket and removed these two studs. That way, the intake can be removed easily.
ON the bottom left of plastic intake, one last black tube that can be easily pulled off by hand. Some type of crankcase vent tube (a 4th one).
I also removed the airbox support bracket that is just left of intake (2 bolts, maybe 14MM).
Now you should be able to change out the plugs.
Installing it all back together:
Before installing the two star studs, you want to first get the12MM bolt started on back, right side of intake. You may have to move the intake up or down a bit to get the threads started. Then, get the left bolt in 14MM on left side. They don't need to be tight, just be sure they are fully engaged.
Then you can install the two star studs. I just snugged them down a bit. Not overly cranking them too tight.
Then intake bolts (after metal bracket is installed). I did not have any torque settings but before removal the first time, I took my torque wrench and dialed it until it just clicked and the bolt moved slightly. That value was 30 ft-lbs.
It's plastic so don't want to crank too hard. I did it a number of times so I think 30 ft-lbs is a pretty safe value. I started at the middle bolt and worked my way outwards for even seating.
Then metal intake, TBI unit....and the rest.
Denso (3297) SK20R11 IridiumSpark Plug
Got them on Amazon for $6.30 ea. You can also pick them up at Advance Auto but more expensive. You may even check out your local Toyota and Lexus Dealer.
As far as instructions, I basically just went for it. I did look at a few "other type of lexus cars" but some of them actually had more stuff to do. There really is only 3 hoses that you need to disconnect, and they are all at the Throttle Body. Two are coolant ones and the shape pretty well defines where each one goes. The other is maybe the crank case vent...something without liquid.
My recommendation, Definitely get some ratcheting type wrenches. I had them already and love them. IF you don't have them, go get some. There are 3 rear bolts that would be pretty difficult to remove otherwise. But pretty easy with a ratcheting wrench.
Because I just joined the forum, I can't post pictures for 30days. So can't really do a play by play for you.
I did not replace any of the rubber gaskets as some other threads pointed out. Mine seem to be in decent shape. I also didn't do the PCV valve.
Some note worthy key things I can recall.
After removing the throttle body unit (where the electrical connector and 3 hoses plug into), there is a 12MM bolt on right side that holds the intermediate metal intake between the TBI unit and the plastic intake. Then the surrounding bolts and nut to remove from plastic intake.
Two bolts on back side of plastic intake. The one on right side (after metal intake is removed), is a 12MM. The other one is on left side and is a 14MM (I believe).
Once all the intake bolts are removed, and the two nuts....there will be two star studs still holding the plastic intake in place. I used like a 7/32 socket and removed these two studs. That way, the intake can be removed easily.
ON the bottom left of plastic intake, one last black tube that can be easily pulled off by hand. Some type of crankcase vent tube (a 4th one).
I also removed the airbox support bracket that is just left of intake (2 bolts, maybe 14MM).
Now you should be able to change out the plugs.
Installing it all back together:
Before installing the two star studs, you want to first get the12MM bolt started on back, right side of intake. You may have to move the intake up or down a bit to get the threads started. Then, get the left bolt in 14MM on left side. They don't need to be tight, just be sure they are fully engaged.
Then you can install the two star studs. I just snugged them down a bit. Not overly cranking them too tight.
Then intake bolts (after metal bracket is installed). I did not have any torque settings but before removal the first time, I took my torque wrench and dialed it until it just clicked and the bolt moved slightly. That value was 30 ft-lbs.
It's plastic so don't want to crank too hard. I did it a number of times so I think 30 ft-lbs is a pretty safe value. I started at the middle bolt and worked my way outwards for even seating.
Then metal intake, TBI unit....and the rest.
What ignition coils did you buy exactly, please, because I can find so many and for different prices?
Thank you
Kind regards
Thread Starter
Pole Position
Joined: Apr 2016
Posts: 234
Likes: 26
From: CO
Denso 6731301 Ignition Coil
https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1
Lead Lap
Joined: Jun 2013
Posts: 527
Likes: 56
From: MA
Normally wouldn't post in a thread I can't contribute to technically, but I want to say thanks to the op for making this thread, and also following up with the solution. Hopefully I won't have to do my plugs until 200k, but at least now I'll know what's involved!
Racer
Joined: Sep 2014
Posts: 1,811
Likes: 91
From: Scottsdale, AZ
I believe the spark plugs on this one the 400h; are the same as on the 330 and 350. The front 3 are super super easy!; about 20 minutes and its done; the rear one however are a whole different ballgame. The rear ones are a royal $@!%&!!!. among other choice words lol. with the help i had it took 3-4 hours to get the rear ones done as ya gotta remove the manifold, intake, and several other things just to get to them. And by the way; if ur gonna diy the rear plugs u should consider doing the rear coil packs at the same time because if u button everything back up w out doing the coil packs; and at least one of them goes out; then ya gotta go back through and undo everything all over again. just some food for thought here as well as my 2 cents.