Surging during light to moderate acceleration

I think the low octane causes a dirtier engine internally. I might be wrong there though. Also we are mainly talking about ethanol levels. And our flex fuel trucks getting that ethanol level wrong. I've seen my truck read an ethanol reading of 14% when the gas was supposed to have a max of 10%. When the flex fuel trucks read higher ethanol readings they supply more fuel. Causing issues. Hard starting etc .

 

Interesting to see better mpg from the lower octane gas though. I mainly run mid grade to keep down on low octane ping that I've had in many vehicles when running low octane gas.

 

For the first time since hooking up the obd scanner my ethanol reading was a little high. 13.3% but no surge. I always check to see what it is after getting gas. Now that I've drove about 75 miles the reading is back down to 7%. Still no miss/surge.

 

Well. Truck done it's miss/ surge today. Ethanol % was at 7.8 when it first started surging. Was pretty low on gas so I stopped and got gas. Ethanol % jumped to 29. Went down to 23% a couple of miles down. Surged all the way home. Now what do I do? Call my local dealer ship and tell them my findings? It went from January 13th till today and never skipped a beat. All of a sudden out of nowhere it starts doing it again. Talk about intermittent. A month between it acting up.

 

I have a 2010 dclb with 5.7 flex with 230k and have had this issue since about 125k. I have found it is humidity and moisture related to an extent, and is very intermittent. Sometimes when idling for an excessive period of time without moving it will also develop a rough idle and flash an engine light, when this happens it appears to misfire all the way from idle to about 3000 rpms.

The surging happens between 2100-2800 rpms in any gear, even when held in gear. It happens in any throttle as well. Drove to Charleston, SC from Nashville last summer, it surged the whole way there. Drove around Charleston and all the way back and it acted like a brand new truck. I have been told I’m feeling the torque converter opening and closing or engaging, but it is probably not the issue. I haven’t tried to change tps, but I’ve heard they can go bad and not throw a code.

I am beginning to wonder if it has to do with the battery and or cables. I know it sounds stupid, but I have seen other trucks surge like this and then they work great after cleaning the battery terminals. It could be resetting the CPU that helps, but once cleaned they seem to not act up for several months. Thoughts?

I’ve been through all the steps you are taking, and we are still here.

 

I'm seeing the surge only when the ethanol reading is high. The lower it is the less the surge is felt. But from what I have read there isn't a sensor that tells what the ethanol % is. It is calculated from the other sensors. So it could be an oxygen sensor MAF etc etc. It's been surging for the past 3-4 days. Clueless where to even begin. I'm considering buying techstream and a cable for my laptop and doing the relearn procedure for the ethanol. Might be my cheapest way of finding the problem.

 

If you have a check engine light you can read or have the code read and you should be able to pinpoint the problem. I'm yet to see a check engine light or any codes.

 

Ethanol % down to 7.8 again. Running like a champ. This is frustrating. Fuel trims were in the negative when the ethanol % was high. Any advice? I'm convinced the high ethanol % goes hand and hand with the surge .

 

After dealing with this for the past few months I guess I'm just gonna order the $500+ fuel pump and hope for the best. I've read plenty of threads from tundra talk on the situation and guess that's my next move. It's sort of an educated guess. Wish I had concrete evidence but I don't.

 

Bring to toyota and have your FFV recalibrated if ethanol level is high.

https://www.tundras.com/threads/rough-cold-start.36837/#post-954308

 

Not sure the tsb covers 2011. I'll call them again tomorrow. Service manager was supposed to contact me about the cost of resetting the alcohol density but he has not returned my calls.

 

Does it only happen when engine is cold?

 

Nope. Constantly and the hard to start symptom usually associated with the high ethanol reading is not there. It fires right up every single time.

 

Mine does it only if I drive it before it warms up. Was thinking MAF

 

On mine I'm afraid it could be anything that affects fuel trim and air fuel ratio. Guess it could be a MAF. I'd be throwing parts at it at this point. $89 for the alcohol density relearn. However I'm afraid that'll only last until I get gas again.

 

my 2006 Tundra/4.7L/ 215k miles has just started surging. seems to only happen between 2100 - 2800 rpm and under a load, like accelerating to get on the interstate.
I have noticed that since the surging began, My avg mpg went from 16.7 to 18.1. Ive owned the truck since new and kept a close check on mpg. never got over 17 until now. what could this mean?

 

Coldjustin, so did u put a fuel pump in it yet? Fix the issue? I have a 2011 FF and it’s doing same stuff too

 

I have not replaced the fuel pump yet. I was hoping someone else having the same issue would replace theirs and report back if it fixed the problem. My truck still has the issues. It comes and goes and luckily so far it hasn't been a big deal. I worry it's causing my truck to run lean though and might be hurting the engine, converters etc .

 

There was a guy by the name Medic1 on another post on here I read today that his did this surge also. Finally he got codes and CEL etc and has to put a fuel pump in it. Posted after that the surge was gone and even after 10k miles came back and said the surge still is gone. So I’m leaning toward it being a fuel pump issue just hate to take the plunge if that isn’t it for $700.

 

I'm gonna compare some prices and possibly order a fuel pump tonight. I'll put it in as soon as I get it. I'll let you know if it takes care of it. It can't be good on the engine to run lean for this long.

 

Thanks

 

Dang! Cheapest I can possibly find is well over $500. Guess I'm gonna bite the bullet and order it tonight off of rockauto.

 

Dam son. That’s shitty. Is rock auto like oem for the fuel pump?

 

It's not OEM. I think it's Delphi brand. Can't remember. The most expensive I've seen is $700. $484 for the Carter brand. Never heard of that brand and I'm not sure how good the warranty is. I've got a neighbor and good friend that works for NAPA. Think I'll give him a call in the morning and see what he can do. I don't mind the $500 if it fixes the truck and is a good quality fuel pump that'll last at least 3 years .

 

Anyway to find out the oem Toyota part number for my trucks fuel pump? So far I'm seeing it as a 770200C090 but im not willing to order the $300-$400 part and be taking a guess at it.

 

$529 from my local dealer and it can be here in the morning. Anybody got a connection to Toyota parts before I pull the trigger?

 

https://parts.toyotaofcoolsprings.c...7l-v8-gas/fuel-system--fuel-system-components

 

Any word on finding a deal on oem pump ?

 

I have had engine surges for several months now and i have been reading this forum trying figure out what might be going on. I finally noticed i was having a lot of oil leaking from the valve covers, so i got a new valve cover seal kit and a new PCV valve. When i went to take the bolts off the covers i discovered they were barely even hand tight! Then when i took out the old PCV valve, it was completely clogged with oil/ dirt/ grime. Popped the new in and put everything back together and no more surging! The engine is now responsive like it used to be, and is shifting like it should.

 

This is common on our 1st Gens. Loose VC bolts and leaking covers with a gunked PCV valve.

Another maintenance issue is a dirty Throttle Body. Clean with a soft toothbrush and Throttle Body Cleaner.