Have put together a new smoke machine and I'm looking forward to this weekend when I will have access to the LR3 to try this. My fingers are crossed! Hoping to find an air leak between the air filter and the throttle. But fearful it might be a more difficult repair. As y'all can tell I'm pretty new to me trying auto repair.

As near as I can tell auto repair takes 3 things: 1) a decent place to work, 2) the necessary tools to actually do the job and 3) knowledge. I'm lacking all three! But . . . I'm making progress on #2 & #3 (slow progress but still moving forward none the less! I was an ultrarunner and I'm used to the mantras "Rentless Forward Progress" and "Run when you can, walk when you have to and crawl if you must!"). But no garage or awning and fairly steeply sloping gravel driveway are super limiting for #1

 

Smoke machine seemed to be a big success! Definitely found two air leaks where the plastic cracked just downstream of the MAF sensor and on the other side of the plastic resonator connection well before the throttle. I sealed these up with epoxy. It took me "two forevers" to get everything aligned and reinstalled! SMH. But I'm very hopeful, as we didn't see any leaks around the engine itself. I guess time will tell.

 

And time did tell! Another dry hole. Check engine light returned within a day.. I'm going to repeat the smoke test this weekend. See if I can find any more air leaks. But yesterday I had another idea. A week or two before these codes started appearing I had had a shop replace the fuel pump. I am wondering, could it be the fuel pump pressure is too low. I understand it should be about 50 psi, so I'm gonna check that this weekend when my wife brings the car up to me.

So far I've:

• Replace the PCV valve.
• Cleaned the throttle (not a thorough cleaning job, but it didn't appear too terribly dirty)
• Ran injector cleaner through the fuel
• Cleaned the MAF.
• Replaced the MAF
• Ran a smoke test and found two air leaks upstream of the throttle . . . no air leaks discovered downstream (valve cover gasket, injectors, etc)
• Sealed 2 air cracks in the plastic air intak

Any suggestions would sure be appreciated!!

 

I am in the same boat for regarding the Codes- basically since 2022. I am due to get the 07' LR3 (136k miles 4.4) re-registered in Northern Virginia, which requires an emissions test. The codes and CEL will automatically fail it, placing me in a conundrum. Having spend a least a couple thousand dollars chasing this gremlin (replacing EGR, MAP, MAF, O2 sensors, air intake resonator, fuel system flush) I am trying to think of a strategy to address the situation. There is a provision that allows a failed emission vehicle to be registered if repair costs exceed $1,000. Chasing down gremlins takes time and with hourly rates pushing $180 for independent LR mechanics a resolution will quickly hit that $1000 threshold. Figured I'd just fail it, and at the same shop look for a leak up to that total cost vs. trying to actually address the situation. It runs fine, no drastic decrease in efficiency or any other engine issues.
I would do it myself, but it is not a straight forward repair, I can swap/repair install minor to moderate things, but chasing potential leaks or electrical anomalies is just something that would be out of my league- (time, cost, quality iron triangle).

 

I guess I'm pretty lucky that WA state did away with emissions testing recently.

 

Yea, its unfortunate that its an automatic fail with a CEL on the dash; and a bit of a shakedown, basically paying the shop 1k to wave the requirement. It is only in certain counties in VA, I happen to live in one of the ones. I am surprised WA did away with it, given the politics of WA state. I am all for clean air- but the increasing restrictions start to be regressive.

 

I fought this battle a long time with cracked intake plenum, EGR smoke, isolating the evap and PCV, cleaning the MAF, recleaning the MAF, trying to make sense out of live MAF data correlated with Fuel trims, etc. Temporary positive results ended up in the lean codes eventually coming back. I figured it may be valve cover or timing cover leaks, and I would just live with it like many have.

Somewhere I stumbled across that my elderly mother's 2000 Toyota 4Runner uses the same MAF as our LR3's. I did a swap-aroo and to my surprise I had no codes on both vehicles. I've been wanting to report back here with a detailed live data graph of MAF, LT, ST, etc. so that others could measure their MAF data against a known good and a known bad MAF profile, but I've been unable to do that.

I installed a new DENSO 1976020 MAF for a 2000 4Runner (RockAuto $88 + tax and freight) in my 06 LR3, gave Mom her original one back, and both cars are still happy. I'm still surprised, but enough time has gone by to confirm. With no other changes other than the MAF, fuel trims are much tighter across a full acceleration range with the new MAF causing both pos (lean) and neg (rich) fuel trims where the old MAF caused only positive fuel trim which would go high enough and often enough to trigger lean codes.

I'm not suggesting people go out and buy another new MAF to solve the problem, but identifying a legit good MAF live data graph could be helpful to many in confidently confirming a good/bad MAF. If I figure that out one day, I'll post it here. There are so many crappy aftermarket and even OEM parts that may be bad right out of the box leaving us assuming or guessing.

Good luck all and hope you find a permanent solution!

 

A bit like the mother in law, I've come to learn to live with my CEL P170-00 or the various iterations that pop up. I've lived through replacing injectors, gaskets, PCV, MAF, EGR, o2 Sensors, smoke tests etc, and my annual PA emissions test is fast approaching. The last inspection I replaced the EGR and was probably clear of the CEL for 2-3 months, without doubt the longest time in 6 years of ownership.

The latest error, P0170-00 (E8) Fuel Trim (bank 1), pops up pretty quickly after clearing. Checking the FTs, they seem to spike when decreasing speed around 1500rpm then settle once again pretty quickly. This is the only indicator I can see when monitoring FTs.

However, I do have an issue when I have a 1/4 tank of fuel or less, and coming to a stop on a downhill road, the car will stutter or stall. I also get this when going downhill turning right, which leads me to believe I've likely got a failing fuel pump, so this is my next area to address. I don't have the space to do this one myself, so will be one for the shop to switch out when I send it for inspection.

Will keep you posted and update the outcome in a few weeks.

 

So having struggled with the P0171-P0174 Lean codes for 2 years and numerous sensor changes (MAF, MAP, O2 (up and down stream) amongst sundry other attempts from a local shop and myself and facing an emissions requirement for registration, I decided to take this gentleman's Hail Mary of a suggestion and try the DENSO 1976020 MAF used in a 2000 4Runner. It was 100 bucks and with an emissions waiver totaling in excess of $1000, I said what the hell. Welp- I can say now, that dreams do come true and Santa is real and the Dang Toyota MAF worked.
I installed cleared adaptation settings and watched the Fuel trims with the GAP II Tool. after 200+ miles and no CEL, I went to the emissions shop and wouldnt you know it - it passed! God damn! Thank you P-Bod, Clearly not all hero's wear capes (or maybe you do wear capes? I mean I am making an unfounded assumption...)

 

That's great news jbullock78! Mine is still good after 1,000+ miles and at least a couple of months. I'm glad it worked for you. No cape, for the record, not a hero, but thanks for your kind words and sharing your success with others. I have benefited greatly from this forum and try to contribute where I can.