Quick backstory. Bought this cruiser just under a year ago. Overall very clean but I have been slowly baselining things. About a month ago I replaced PCV, all vacuum hoses and cleaned throttle body and MAF sensor. Replaced fuel filter, checked torque on spark plugs, recently replaced 2 coils and rebooted several others. No vacuum leaks suspected. A smoke test confirmed no vacuum leaks as well. O2 sensors aren't that old (20k miles ago).
The truck :
2007 Land Cruiser. 211k miles. Non AHC from factory. Bone stock. VERY well maintained with full service history. DOES have a Hewitt SAIS bypass installed (plug and play edition - I will be hardwiring it ASAP like I did in my 4Runner)
THE FIX: note that this was a 2 part fix...
Part 1
You can read the background and attempted fixes below, but I ended up taking it to Ryan at OTRAMM. I'm lucky enough to live 20 mins away! It took some digging on his part as it only threw the CEL once during these 2 weeks of issues and I had cleared the code (and any stored data) w/ my cheap scantool - Whoops! Ryan ended up narrowing it down to the throttle body. He "re-initialized" the throttle body and since then it's been running perfectly again. It's worth noting that fuel trims, voltages, everything was 'in spec' during most of the test drives (I drove him around for one, then he did several others during diagnostics). He did note that fuel trim was on the high end of the range before the throttle body fix and post re-initialization it had lowered.
Part 2 (new edit)
The work that Ryan did in part 1 made it drive 80% better. As I drove it for a week or two after OTRAMM work, it was evident there was still something going on. I messaged a bit with @2001LC and did some poking around and decided to pull the manifold. So after the OTRAMM work, I ended up replacing fuel pressure regulator and damper, new denso fuel pump. Rebuilt all the fuel injectors with new filter baskets, o rings and insulators. Did ultrasonic
cleaning and flushed them out. They were quite dirty. Replaced intake manifold gaskets (someone had been in there before and used aftermarket gaskets w/ gasket maker...what a huge mess and was obviously leaking a small amount) and de-carboned the intake manifold and intake ports (thanks @OEMGUY0720 for the tips) with Berryman B12 (that's harsh stuff btw). Cleaned the throttle body really well this time (was able to get to the backside of it). New TB gasket. New IAT sensor. Hardwired the SAI bypass and took apart all the valves and pump while I was doing the gaskets and starter. Foam had degraded and blocked up the ports in the valves as predicted by 2001lc. Added the pre filter just to have the system sealed up at both ends.
So, basically the entire fuel delivery system is cleaned and new. All air intake passages are cleaned like new. The Throttle body 6 pin connector had been broken by someone prior to my ownership, so depinned and repinned the new connector.
NOW it runs very well again. Great throttle response, no lag or hesitation. Feels like a new truck.
Thoughts:
Did I tweak something when I cleaned the throttle body? I did it the same way I've always done it, didn't disconnect the battery or anything, and yeh, I know that's not 'by the book' but I never had an issue in my V8 4Runner 2uz VVTI over 10 years with regular cleaning. I think it was a combination of factors here, intake manifold leak, dirty injectors, bad MAF? and for some reason things seemed to all take a dump together. Maybe cleaning and replacing some other stuff created the issue knocking something else loose.....honestly no idea. just happy it's working again. I do have some new upstream O2 sensors I will be throwing in soon as well.
THE ISSUE:
2 weeks ago, started experiencing intermittent stumble on acceleration but WOT (wide open throttle) was no issue. It would get up and go. First day it threw P0101 (MAF sensor), P0172 and P0175 (banks 1 and 2 rich condition). I cleared the codes on the side of the highway so I could get to my work meeting and carried on. It would run ok, but then randomly stumble until I gave it more gas.
It never threw any more codes so I started working my way down the list of possible issues. Checked air filter, cleaned MAF again, disconnected the SAIS bypass, swapped in the MAF sensor from the 4runner. Nothing helped. Some people had issues that were fixed with a new MAF connector so I ordered one of those. Considered it may be IAT/ECT sensor. Checked all coils and plugs again just for kicks. Checked vacuum hoses. Disconnected battery to reset everything. No change. I have a fuel pump, fuel regulator valve and was getting ready to start throwing parts at it...
But with a trip coming up and since it hadn't thrown any more codes but was still 'off' and needed the truck running properly, I called Ryan and took it to him. Really appreciate that he was able to find it quickly and fix the issue. I don't have techstream so not sure I would have figured this out without his help.
Hopefully this helps someone else that ends up in this situation or has these codes. I used these couple threads while I tried to solve the issue myself:
forum.ih8mud.com
Image below blatantly stolen from one of jerryb's posts
The truck :
2007 Land Cruiser. 211k miles. Non AHC from factory. Bone stock. VERY well maintained with full service history. DOES have a Hewitt SAIS bypass installed (plug and play edition - I will be hardwiring it ASAP like I did in my 4Runner)
THE FIX: note that this was a 2 part fix...
Part 1
You can read the background and attempted fixes below, but I ended up taking it to Ryan at OTRAMM. I'm lucky enough to live 20 mins away! It took some digging on his part as it only threw the CEL once during these 2 weeks of issues and I had cleared the code (and any stored data) w/ my cheap scantool - Whoops! Ryan ended up narrowing it down to the throttle body. He "re-initialized" the throttle body and since then it's been running perfectly again. It's worth noting that fuel trims, voltages, everything was 'in spec' during most of the test drives (I drove him around for one, then he did several others during diagnostics). He did note that fuel trim was on the high end of the range before the throttle body fix and post re-initialization it had lowered.
Part 2 (new edit)
The work that Ryan did in part 1 made it drive 80% better. As I drove it for a week or two after OTRAMM work, it was evident there was still something going on. I messaged a bit with @2001LC and did some poking around and decided to pull the manifold. So after the OTRAMM work, I ended up replacing fuel pressure regulator and damper, new denso fuel pump. Rebuilt all the fuel injectors with new filter baskets, o rings and insulators. Did ultrasonic
cleaning and flushed them out. They were quite dirty. Replaced intake manifold gaskets (someone had been in there before and used aftermarket gaskets w/ gasket maker...what a huge mess and was obviously leaking a small amount) and de-carboned the intake manifold and intake ports (thanks @OEMGUY0720 for the tips) with Berryman B12 (that's harsh stuff btw). Cleaned the throttle body really well this time (was able to get to the backside of it). New TB gasket. New IAT sensor. Hardwired the SAI bypass and took apart all the valves and pump while I was doing the gaskets and starter. Foam had degraded and blocked up the ports in the valves as predicted by 2001lc. Added the pre filter just to have the system sealed up at both ends.
So, basically the entire fuel delivery system is cleaned and new. All air intake passages are cleaned like new. The Throttle body 6 pin connector had been broken by someone prior to my ownership, so depinned and repinned the new connector.
NOW it runs very well again. Great throttle response, no lag or hesitation. Feels like a new truck.
Thoughts:
Did I tweak something when I cleaned the throttle body? I did it the same way I've always done it, didn't disconnect the battery or anything, and yeh, I know that's not 'by the book' but I never had an issue in my V8 4Runner 2uz VVTI over 10 years with regular cleaning. I think it was a combination of factors here, intake manifold leak, dirty injectors, bad MAF? and for some reason things seemed to all take a dump together. Maybe cleaning and replacing some other stuff created the issue knocking something else loose.....honestly no idea. just happy it's working again. I do have some new upstream O2 sensors I will be throwing in soon as well.
THE ISSUE:
2 weeks ago, started experiencing intermittent stumble on acceleration but WOT (wide open throttle) was no issue. It would get up and go. First day it threw P0101 (MAF sensor), P0172 and P0175 (banks 1 and 2 rich condition). I cleared the codes on the side of the highway so I could get to my work meeting and carried on. It would run ok, but then randomly stumble until I gave it more gas.
It never threw any more codes so I started working my way down the list of possible issues. Checked air filter, cleaned MAF again, disconnected the SAIS bypass, swapped in the MAF sensor from the 4runner. Nothing helped. Some people had issues that were fixed with a new MAF connector so I ordered one of those. Considered it may be IAT/ECT sensor. Checked all coils and plugs again just for kicks. Checked vacuum hoses. Disconnected battery to reset everything. No change. I have a fuel pump, fuel regulator valve and was getting ready to start throwing parts at it...
But with a trip coming up and since it hadn't thrown any more codes but was still 'off' and needed the truck running properly, I called Ryan and took it to him. Really appreciate that he was able to find it quickly and fix the issue. I don't have techstream so not sure I would have figured this out without his help.
Hopefully this helps someone else that ends up in this situation or has these codes. I used these couple threads while I tried to solve the issue myself:
Intermittent rich codes and SAIS?
Ive been battling these codes 0172/0175 off and on for a while. Firstly I did change the MAF a while ago, this did work for a while, then the codes came back. Even if I'm not getting the light, I can tell by the way the truck drives. ie holding gears, rough idle, erratic shifting and revs...
forum.ih8mud.com
Image below blatantly stolen from one of jerryb's posts
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