Sputtering 2.7

Hey all, just wondering if anyone thinks the idle sounds…uneven on my taco? I can feel a bit of vibe or misfire but no codes at all. New spark plugs as well.

 

https://youtube.com/shorts/bYHZnWnVXqE?feature=share

 

So many details. Mileage? What's been replaced? RPM and moving speed you're experiencing misfire? Video of engine under the hood? An exhaust vid only gives so much.

 

I listened to that video about 4 times. TBH I don't hear anything out of the ordinary.

 

124k miles. Tons of idle hours (I’m a smoker in a cold state). 2012 auto. Brand new spark plugs, cleaned MAF sensor, new afr sensor, slight exhaust leak, but it’s after the cat so shouldn’t affect it. Air filter looks clean. I’ve been chasing a vibe that I think is partially tires, partially cv joints?? I have brand new front calipers, brake pads, fairly new rotors though maybe slightly warped? New u joints on the driveshaft. Maybe I’m paranoid but just kind of feels slight shake at idle and pulsing vibe while driving. Maybe motor mounts? Recent trans coolant lines, recent rear diff fluid, recent trans fluid, recent oil change, cleaned up the throttle body door flap thing. Stumped. Noted low coolant at last oil change but after topping off a few weeks ago I haven’t lost any. Praying there’s not like a slight head gasket leak or low compression or something.

 

It’s sort of the fast paced bububububub sound to me? Like a putting sound? Not sure. Never had a 4 cyl before this truck. Used to i6 and v8

 

Check your idler pulleys and water pump

 

Sorry I’m not very knowledgeable but how would I check those?

 

If the Taco you're talking about is a 2012 with x number of miles on i

Before you chase what you think is an abnormal sound or vibration too hard, you might want to spend some time listening to at least a few other 4-cylinder Tacomas, preferably in person, to get a baseline for what "normal" is. (Or, search youtube if in-person isn't feasible.)

They have a different sound than V6s for sure. Part of the reason there may be more "put put put" sound is simply that for the same approximate crankshaft rotation speed at idle, there are fewer cyclinders firing per rotation, & it's thus easier to hear individual cyclinders firing.

 

Ahhh that makes a lot of sense. That’s what I was trying to describe, a sound like some cylinders are rhythmic or louder than others. As for the vibration, it may be unrelated to firing order. It’s definitely there though, bc the truck didn’t always do it.

 

Of course it's possible there are subtler issues that maybe you can hear but aren't making it through in the audio recording.

If you have access to an oscilloscope or graphing current clamp meter you might try a relative compression test to get a quick read on whether some cyclinder(s) are considerably weaker/lower compression than others.

This test is non-invasive & pretty quick and easy to perform if you have the right equipment. (No removing sparkplugs, disabling fuel system, bypass cold-cranking, etc.)

https://www.youtube.com/watch?v=0P0CPRFLmww

 

Take the serpentine belt off and spin all of the pulleys, if you find one that spins with little resistance or makes noise it needs to be replaced. I am doing that today. Look at the underside of the water pump, there's about a half inch hole and if you see Mineral buildup that tells you the water pump is working on failing and needs to be replaced

 

Thanks! I’ll take a look when I get the chance! Big snowstorm coming in early this week lol

 

Thanks! If it worsens I’ll probably do that. It’s weird at idle it’s not an evenly-spaced shake. It’s like 1 time every second but not exactly on.the.dot. If you know what I mean. It’s like, smooth for a second, then 2 shakes, then smooth, then one shake, in random order and timing. Super weird. Very very subtle though. At idle you have to be sitting for a few minutes and you just barely feel it in the seat

 

That's pretty normal for these engines. Don't forget they also have hydraulic lifters so they will idle a little rough when cold.

 

Yeah mine knocks in the cold on startup but it’s done that for the last 30 or 40k miles lol. Is there a valve adjustment interval on these?

 

FWIW my 4.0L V6 1GR-FE with 69K miles & 9 years of age on it idles about the same when fully warmed up, with random-seeming low-intensity "shakes" at rate of 1 to 4 Hz or so interspersed with smooth operation. An actual (not relative) cold compression test showed all cycls with high (>190) and fairly even compression (within +/- 10 PSI, which is within manuf. specs.) Haven't run a relative comp. test yet due to lack of equipment. I wonder if it's just the engine mounts having softened up with a decent amt of aging & mileage on them.

 

Could be part of my problem. She’s at 124k and a LOT of engine starts and idle hours