toneekay

So I'm going to copy this over here from the SC section (that I bumped from the dead) into our 2GS section since it might gain a little more traffic. I'm having misfiring issues and it seems that 2 of my injectors are not operating at their full capabilities. The way I've checked these were just putting a flathead onto the base of the injector and listening to the pulsating sounds. Cylinder 2 sounds slow opening/closing (clicking) than all of the others, and cylinder 7 sounds somewhat abnormal sometimes. From my OBD2 scanner, I originally had Cylinder 2 & 7 misfiring, however now it seems like like only cylinder 2 (and maybe 3) is misfiring. Cliffs at the bottom.

Anyways, I'm looking to replace all of the injectors because cylinder 2 injector is most likely bad or on its way out (causing the misfire). I'm looking at the link below showing "Denso 23209-50030" part numbers, however they're all identical and from the quote below, I believe the rear 4 injectors require insulators. I'm just curious if these are actually needed, or if I can install the rear 4 injectors as is.

https://www.ebay.com/itm/Motor-Man-L...75.c3#viTabs_0



Back history:
- Bought car used literally last week with about 194K miles on it
- Previous owner mentioned he had timing belt, water pump, and valve cover gaskets replaced
- Car was/is misfiring, and I still decided to pick it up thinking I can figure this out and fix it and have a cheap-ish DD to roll around in
- I trusted previous owner because we was very thorough and detailed with everything on the car

My diagnosis on the misfires:
- Cyl 2 & 7 originally misfiring
- Cleaned TB & MAF sensor
- Swapped coils from 2 to 4 & 7 to 3
- Still misfiring on both the same cylinders
- Pulled plugs, noticed that there were a mix-match of spark plugs:
Cyl 2 plug - NGK ZFR5FGP
Cyl 3 plug - DENSO IK20
Cyl 4 plug - DENSO IK20
Cyl 7 plug - DENSO SK20R11
- Cylinder 3 & 7 had oil on it leading me to believe that the VC gasket job was botched and/or spark plug gaskets were not replaced or replaced incorrectly
- Cleaned off coils and replaced Cyl 2 & 7 plugs with brand new DENSO SK20R11 (literally the only plugs in stock ATM at local parts store)
- Cylinder 2 is still misfiring, however now cylinder 3 is misfiring, but 7 is not
- Believe cylinder 2 is misfiring due to bad injector
- Haven't diagnosed cylinder 3 much further since that day as it comes and goes (clearing the code, driving short distances, clearing the code, repeat, etc...)


Any other thoughts would also be greatly appreciated. Thanks!

silverbul

I had the same problem with my GS400. Oil was leaking on the plugs and fouling them up & my car would smoked at start up if it sat overnight All I did was was changed both vc gasket, very easy to remove, new plugs, cleaned my coil, clean my intake with seafoam. Back to normal

toneekay

Yeah I'm pretty sure that's what's happening on the driver side (bank 1?). However, the cylinder 2 & 4 are both clean with no signs of leaks. That's why I'm wondering about the injector(s).

I've also read a number of other things like failing O2 sensor, VVTI OCV, etc that would cause a misfire, but I don't want to look into those yet as I'd like to eliminate the most "common" problems first.

silverbul

My car has 270k miles on it and I never changed my injectors. Ocv is easy to change. Unplug the sensor and 1 10mm screw, pull it out & put it back in

toneekay

Yeah I looked up the manual and that's a pretty straight forward install, but the I don't want to spend the $50-60 if that's not my issue either...

kevin3344

Probably not an injector problem...I've never had a problem and I've got 230k on mine. It could be due to mismatched plugs. I would start with true OEM spark plugs (you can get them from your local Lexus dealer) and make sure your VC gaskets are not leaking. Once all of your spark plugs match you'll be in a better position to troubleshoot the problem. Sounds like the previous owner had a misfire issue and tried to replace one plug at a time.

Edited to add: you can clean your OCV you don't have to replace it.

silverbul

Change your valve cover gaskets and make sure the spark plug ring gasket are not damaged. That's how the oil gets on the plugs and foul them up. I also used this device I got when I worked at firestone that I used to connect to the intake & I poured seafoam into it & ran it thru to burn out any oil & carbon buildup. Car has to be running at 2k rpm. Intake sucked the seafoam thru the device. Car is fine now

toneekay

That's the next to do list since it's the most crucial - Replacing the VC/SP gaskets and dropping in a fresh set of OEM plugs since it's still fairly cheap and easy fix.

As for the injectors, I'm convinced cylinder 2 is bad since there's no oil leak on that whole side (cyl 2, 4, 6, 8). Just thinking ahead on the issue on that side since that cylinder is the only one that keeps showing up. It's like I'm diagnosing two different misfire issues on two different cars, but really it's just one lol.

silverbul

Buy coil packs. They're go bad before the injectors would. If you swap the coil packs and that cylinder fails its that coil pack that's bad

toneekay

Okay, so I'm pretty stump now... So far I've done the following below and still coming up with a cylinder 2 misfire.

- Changed the VC/SP gaskets
- Installed a fresh set of matching spark plugs
- Swapped coils from cyl 4 to 2
- Swapped injectors from cyl 4 to 2
* Cylinder 4 is a known working cyl for plug/inj
- Checked compression (dry), all cylinders are between 160-175 psi
- Changed both VVTI OCV to new units

Right now my next to check list is to check electrical connections to see if there are any physical damage to wires. A buddy of mine also mentioned that I may want to do a valve job next as well.

Is there anything else that I'm missing that I should be looking at?