Cold start misfire 2013 2tr-fe 2.7l

OBD data shows MAF at .43lb/min (which is a little low). It's got new plugs and coils. Does that mean I need a new maf? Have cleaned it a couple times, nothin' doin'. It has a code for cylinder 2 misfire. Anyone live in Central Indiana and able to meet to trade me an MAF for ten minutes to try to rule that sensor out. What else can I rule out with OBD and or multimeter, before I go buying anything?

 

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Lb/min, sorry

 

Depending on engine speed that's pretty close for idle (rule of thumb is 1 g/s per liter of engine displacement at hot idle)

0.43 lb/min = 3.25 g/s

Is it a particular cylinder that is misfiring?

Are you losing any coolant?

 

Had a small bit of coolant missing, so suspected head gasket. Checked compression, it was ~160 to 165 on all four cylinders.

 

Thought about swapping an injector, but if that ends up being the problem, I really want to just swap in a new injector to send the old one off for cleaning. That way I have a spare.

 

A very small headgasket leak that would cause a cold start misfire but no other symptoms wouldn't show up on a compression test and may not even show up on a combustion gas test.

Best method to check is either run the truck up to temp, and let it sit overnight then pull the plugs and use a borescope to check for coolant in the cylinders or use a cooling system pressure tester to pressurize the system and let it sit several hours then check for coolant in the cylinders.

If the test is positive you have a headgasket leak, if it's negative then you can pursue other possible causes.

 

I did the coolant pressure test, and didn't lose any pressure. I chalked up the coolant loss to water evaporation.

 

You probably wouldn't seen much if any pressure loss, it only takes a teaspoon or so of coolant in a cylinder to cause a misfire on startup that lasts a few seconds.

Super easy to pull the plugs on a 2TR just to rule that out. While you have them out inspect them for any cracks, carbon tracking, oil fouling, excessive gap, etc.

 

ONLY the #2 cylinder misfires? For how long? Not a MAF issue if only one cylinder is involved most likely. Could you have a leaking injector that pools gas in the cylinder and causes a misfire until it's evacuated and the plug dries? Once it fires, the engine will run perfectly fine until it shuts off and gas leaks past the injector again and build up enough to pool.

 

Yes, only cylinder 2. Sounds like I ought to swap injectors and see what happens. Surely that won't take more than an hour or so.

 

Misfire/rough start happens for maybe ten seconds. Truck has about 125k on it.

 

I'd start with the injector myself.

 

Did you ever find out what the issue was? I have a 2013 Tacoma with 2.7 engine. Throwing a P0301 code. Happens mostly on cold starts then it smooths out. It also when misfired while driving on the highway I pulled over shut the truck off then restarted and it was fine. Next day cold start threw a code. I put in new plugs,new coil packs, new battery (old one was low) took all injectors out and cleaned them (opening them with 12v source) when reinstalled I swapped injectors and put cyl 3 injector to cyl 1. Compression test is 160/165 all cylinders at operating temp. Very little coolant loss. Today took out cyl 1 plug and looked in cyl with inspection camera. Top of piston was black and wet but I think it was fuel. Stuck a long q tip in cyl to absorb the wet to see if it was pink (same color as coolant). It was dark Blackish from the fuel cleaning carbon I guess. I am thinking electrical. Any help is appreciated.

 

Replacing the valve cover and more importantly the spark plug tube gaskets fixed my misfire.

 

why would that cause a misfire?