Surging during light to moderate acceleration

Today my truck really started surging at light to moderate throttle. Truck has 227,000 miles on it. It has been "serviced" at the local Toyota dealer since new. It was purchased when new with a lifetime powertrain warranty as long as all services were performed timely. I called the dealer today and asked if the truck had ever had spark plugs. They searched and found it had never had plugs replaced! 227,000 miles! I went and bought 8 expensive NGK iridium plugs and threw them in. Intake had to be removed to access the front plugs on the passenger side. When I took the air filter box apart I found severe build up in the intake tube leading to the air filter. The flexible tube had what appeared to be a syrup like liquid in it. I'm certain that the throttle body has never been cleaned or it has been a very long time. I didn't get a chance to take pictures because I ran out of daylight at about plug number 4. Got all 8 in without any broken plugs or wrecked threads. Drove the truck, still surging like before. Curious if I should even try cleaning the throttle body and MAF at this point or look into replacing them. Anybody had luck cleaning an intake system severely neglected?

 

Clean the throttle body. But replace the maf if needed. Pull it out and inspect first tho. Don’t just start throwing parts at it.

Does it throw any codes?

 

No codes. After pricing the throttle body I'll definitely be cleaning that. I'll try cleaning the MAF sensor as well. It's pretty bad though from what I've seen in the intake tube .

 

My main concern is deeper than the throttle body and air filter box etc. What's the intake manifold and even the intake valves look like? Concerning to say the least. I've had the truck for over a month. Put a ton of miles on it. Guessing between 2500-3000 miles. Oil level is full. Absolutely zero smoke and no fluid leaks of any kind. I can't complain too much for the miles that are on it. I plan on tearing into the intake this weekend and seeing just how bad it is.

 

Every single 2uz intake I’ve ever seen has been soaked in oil.

 

Replace the in tank fuel filter and/or external one.

 

Game plan for this weekend is to clean the throttle body and MAF and drive it. See if it continues to surge. Then fuel filters if it continues to surge. I want to know the cause and post back here what fixes it. Too many times I see a problem posted and no solution. But you know they got it fixed eventually .

 

Sounds like you've got a good game plan lined out. I am interested to hear how everything works out. My last truck was at 270000 miles when I sold it, never had a surge problem and I never cleaned the Throttle body or MAF myself. I'm sure the dealership would have charged a pretty penny to do that so I would have known about it. I would be interested in your cleaning process - keep us posted.

 

I think it's recommended every 50k miles. My last truck only had 20-30k when I traded it so it never made it that far. My wife had a Camry we bought new and around 50k it began surging much like my truck is doing now. Not as bad but occasionally you could feel it. I feel like low octane fuel is the culprit.

 

So I just read up on Tundra 5.7 misfires and it seems the check engine light won't come on if the misfire is at a rpm well above idle but the misfire can be seen with the proper device to read the data while at higher rpms. I would definitely consider this to be a misfire I just never would have called it that because I'm not seeing a check engine light. Oh what fun this is gonna be. I'm sure the dealer will charge an arm and a leg to even diagnose it. Still gonna clean the throttle body and MAF tomorrow. Then possibly the fuel filters but seems I'll be taking a stab in the dark by doing that. I have a good friend that I work with that has a very fancy snap on scanner. Is it possible to view the misfire and pinpoint it with a good scanner? Like a $3k scan tool? Any info into this will be greatly appreciated.

 

The intake needs cleaning anyway, so don't waste time wondering and guessing, just clean it and see! Good luck and let us know how it works out.

 

Will do. First thing in the morning. It's a Modis edge he has.

 

Throttle body cleaned. It was pretty bad. To the point that the throttle valve had a visible air gap around it. Cleaned it up and got all the build up out to where when pressed closed the valve would close completely. Drove the truck and still has the surge/miss. I want to say it's not as bad but can't say for sure. MAF is drying now but you can't get too carried away with it. Only spray the cleaner in the sensor and try. About to drive it again now. Wish me luck.

 

Still has the surge/miss. It's so light that it's almost hard to feel it. For example it's windy here today and it's hard to determine if it's the wind pushing the truck around a little or if it's the engine surge/misfire I'm feeling. But I'm 99% sure it's still doing it. Just maybe not as bad now. I'm OCD on this kind of thing but for good reasons. I know it's not right and I want my truck to be right. Here's a picture of the intake tube I was describing earlier. Not sure of my next move. Also noticed some moisture or water on the oil cap. Seen this milky oil cap on many vehicles that had crankcase vent problems. Bad PCV for example.

 

Dirty deeds.... Could the aftermarket exhaust be the culprit? I didn't notice the change immediately after installing the exhaust but it certainly wasn't too long after that it began. MBRP dual in single out setup.

 

Here's the oil cap. I haven't noticed any loss of coolant. Not saying I haven't lost any but my radiator is full and plenty in the overflow tank. That would be my luck. A head gasket or something way more major than I want to face right now. Still don't see this having anything to do with the surge though. Just something I noticed today that certainly wasn't there in November when I bought the truck. We also broke a rainfall record this past year so the air has been a little moist to say the least. Zero smoke or oil usage. I pulled the oil fill neck and looked down into that valve cover. Looks pretty clean from what I can see. Milky residue at most of the vacuum line connections but it's not the entire line filled with it. Just small amounts at the connections.

 

After more research on the milky oil cap I feel pretty good about it. I live 5 minutes from work. Seems this is pretty normal if these trucks do alot of short driving. Again no smoke. Pull the dipstick and it's clean. I'm getting close to my first oil change so I'll make sure and do the oil change myself to see what it looks like.

 

Hopefully the final update to this problem. Pulled negative cable and left it off for 20-30 minutes. Surge is gone for now. I removed the cable for a short time after cleaning the throttle body and then again after cleaning the MAF. But I may have not left the cable off long enough? I just went to a spot that I know the truck was surging up the hill and never felt it this time. It's so small it's almost hard to tell it's even doing it. I think the problem is solved. Guess we shall see in time if it returns.

 

Do you have aftermarket filter or intake?

 

Obviously not intake but filter sorry?

 

No, just factory. Toyota dealer replaced it on the last service before I bought the truck matter of fact.

 

I've seen a fuel injection system cleaner done at Walmart and I actually worked there years ago and sold them. Unplug the vacuum line off the brake booster and hook the fuel system cleaner canister up to the main vacuum line. The cars we did them on would run rough and smoke and stink and sound awful about 5 minutes into the bottle of cleaner. Then they would clear up and idle smooth and no smoke etc. I wonder if something like that would clean things up? I sold them and never knew if they actually did any good. For $20-$30 it couldn't hurt to try?

 

I see this with short-hopped vehicles too. Even noticed it on one of mine once. A long drive cleared it.

 

Reassuring to hear that. I have a friend with a 5.3 Chevrolet. The valve covers have ports and vents for the pcv. His got to the point of smoking and actually using coolant. He knew it was a head gasket. Removed valve covers and cleaned everything up and put it back together. No smoking. No more mysterious coolant loss. I wouldn't believe him if I didn't witness it myself. Was curious if the same thing happens on our 5.7's

 

I haven't read of anything like that for our trucks, but I don't read all the posts either. I think the PCV on ours is in the valley toward the front on the engine rather than on a valve cover....I think, I could be recalling something else.

I had a PCV on my 3.4L Tacoma freeze up and that forced engine oil from the spark plug seals on the valve cover that dribbled to the header, that smoked!

 

I did see where the 2 hoses come off the valve covers and meet at a "y". That could possibly be some sort of valve but I didn't investigate it too much. When I pulled the oil fill you can see the valve covers certainly look more complicated inside than the old Chevy 350's! When I done the plugs I had one that had oil on the outside of the plug. It could definitely use valve cover gaskets that include the seals around the plugs. It'll be interesting to see under them.

 

Nooooo! Surging again. Any advice on the next step is greatly appreciated. Weird that it stopped after pulling the battery cable for a short time only though.

 

I'm gonna head to my buddies house and we are gonna play with his Modis edge! First time either of us have messed with it. Hopefully it'll pinpoint a cylinder for me. I'd almost bet it's the one that had oil on the outside of the plug. If it shows us which cylinder is misfiring I'll move that coil to a different location and see if the misfire follows the coil.

 

No misfires found and we both agree the surging happens mostly when the transmission is getting ready to hit the next gear. It's like it gets confused and doesn't know whether to stay in that gear or hit the next gear. Weird thing is it does it even when the next gear is locked out. At this point I have no clue what's causing it and wonder if a trip to the Toyota Dr would be the best bet. Not the cheapest but I'm sure it would save me the trouble and cost of throwing parts at it. Plus I did buy a 1year 12k mile powertrain warranty with it when I bought the truck.

 

Did you install a stock exhaust and see if the surging goes away?