Steering/floor vibes? Clean your MAF

yes, you can also read pending codes with a OBD meter, hopefully so can the dealership

 

For any techs out there, here is a CSV file from my log this morning. I am working from home so I was just checking the boxes and confirming my temp gauges were reading correctly after sitting for over 14 hours. when I started it up after a few seconds I actually heard the misfire this time which can be seen in this data clearly. Also seems the MAF is higher than expected even when engine warming.

 

No codes - I ran them with my OBD meter. Which continues to make me feel like a sensor issue is giving a false positive

 

Another simple, cheap thing to diagnose would be to clean the MAF with a MAF cleaner. The thing is, when I review the service manual there is no mention of cleaning the unit. Per the manual, if foreign matter is present, the manual simply states to replace the MAF. Wondering if these can even be cleaned or if I will do damage by following this procedure?

 

OP, thanks for doing some real data collection. I have all the same symptoms as you, with the exception that i feel my vibes more thru the gas pedal than the steering wheel, gotten much more pronounced the last couple thousand miles. 27k on the truck. I notice it all the time now, and seems to be exaggerated during acceleration. I've not reset my battery in a while to see if this temporarily stops the vibes, mainly because i'm getting relatively good MPG right now. Octane content doesn't seem to mitigate the issue, however my MPGs definitely increase when I run 92 over 87. Also, I only ever fill up at Shell, usually the same location. I'm running the oiled TRD filter, so dirty MAF isn't out of the question.

 

If you back down off the premium to 89, I'd bet that (for awhile at least) you'll notice a reduction in the vibes. Then they'll eventually return again... and changing gas will again reduce vibes for a time. At least that occurred in my case. Also find it odd that folks much more knowledgable than myself indicate that we should not see any improvement / change in performance or MPG with different octane fuel assuming the ethanol content is the same. Both I have witnessed myself. 10% increase in MPGs for premium over regular, minimum with much more low-end get-up-and-go and fewer vibes. But it's short-lived after a tank (sometimes 2) it degrades. In this case, I did the battery reset and after about 2.5 tanks it reverted.

Just to eliminate the simple stuff I did do a coil swap with no changes while on my lunch. Also investigated the cylinder misfires and they do appear to be random - no specific cylinder, kind of all over when it does happen and it's generally just one at a time though sometimes 2 on heavy accel.

Also came across this which I feel is some good reading and the symptoms seem pretty consistent with what I've witnessed. Fuel trims indicate lean, while O2 indicates rich, then vice-versa, with the MAF definitely reading out of the range indicated in the service manual....

http://www.autoserviceprofessional....-what-happens-when-a-mass-airflow-sensor-lies

I went ahead and picked up a can of MAF cleaner and will pull the thing out and clean it when I get time later and report back. If the damn thing IS failing, it's an easy fix. I'll pay ~$90 to keep from having to make my 10th trip to the dealer in the 6 months I've owned this.

 

There's definitely a lot of knowledgeable people with respect to the octane debate, but the empirical evidence is there for some of us. I too experience the short-lived MPG increase, usually about 2 tanks or so. Interesting that the ECU is adjusting in such a way that efficiency is decreased though.

Please let me know your findings with respect to the MAF. To me, it seems like the #1 culprit, but I don't know the functions of every sensor and have not been tracking data like you have. You're my hero.

 

I'm seeing a bit of this myself. Just curious to test the reset I just disconnect the terminal for a short period?

 

Indeed, first time I filled up with Shell V-Power I felt like I found the holy grail. Then it eventually started to run worse than it did on 87...

 

Lots of causes of a rich condition in a modern engine but I would look very hard at the CPS. It would cause this sort of intermittent ignition issue. Please keep us updated.

 

I haven't been looking at the CPS, but how could I test to determine if that could be a potential culprit? Indeed I could see how that would cause similar results, but not sure which sensors or visual inspection would indicate whether I'm on the right track.

If I don't have a pretty clear idea what the problem is, the dealer will simply see no codes and send me on my way as a madman making things up...

 

Hey, OP.... If you are running an oiled filter.... Throw it away and go OEM......

Messed up my 2006 Taco with a K&N.... Cleaned the MAF sensor with the cleaner and removed the filter and it was like I'd added a turbo to the engine.... That damn air filter slowly dirtied up my MAF sensor and I did not notice for a long time..

 

No oiled filter - all factory and it's still looking pretty clean. I've done zero performance mods to the truck, just accessories to haul all of our toys...

 

I've had this issue before and after replacing my CPS. I'm not saying it couldn't be the sensor, but the swap didn't help

 

Clean your MAF. I used the CRC MAF cleaner, doused it with 15-20 big sprays and left on a towel for about an hour to fully dry out. Immediately after re-install, off the line performance was night and day and my vibes have reduced back to what I consider "normal" which is only a slight vibe in the 2k range vs. a pulsing sensation throughout. I'm a bit puzzled still - the MAF didn't visually LOOK too dirty, but there was a little bit of dust in spots. I'll analyze the data and report back at a later time, but I can tell you from the Short / Long FT numbers that it is running normal and the O2 sensors running in the low 3s most of the time with only predictable lean/rich readings on accel/decel. night and day.

I'm not holding my breath at this point, b/c I won't be surprised if it relearns how to suck again... but for now, the MAF seems to have corrected the A/F ratio issue. Feels like a truck again... not a Corolla on it's last leg.

 

Yes!! That's awesome man. Ill do the same on Saturday and report back.

Maybe we'll just have to clean our MAFs every oil change. Glad to hear you got your 2.5k rpm vibes back hahaha

 

Yeah, still not right but it is a characteristic of the truck... engine mounts allegedly, but it's subtle and I can deal with it. In my case it seemed like with the reduced engine power, it wasn't pressurizing the power steering which made every bump pulse through the steering wheel on top of feeling near numbing vibes through RPMs

Time will tell, but this was an easy - if frustrating fix for TODAY...

 

OP, have you tried ethanol free gas? It may not help but worth a try.

 

That's great to hear, excited to give this a try now. It's crazy to think with only a couple thousand miles the maf could be so dirty to cause issues but maybe it's because it's new and assembly lube or misc oils are getting on the maf.

 

Yes, have tried E-free and loved it but it also succumbed to the same 2-tank rule of degrading over time. I have easy access to BP ethanol free though so with the MAF cleaned I'll probably try another fill up at some point.