Cylinder 3 misfire after starting warm

Hey all, I bought a '02 2.7L manual 4x4 with ~250k mi about a month ago. The MIL was on when I bought it for a few EVAP/EGR related issues (P0442 - EGR flow excessive, P0440 - EVAP emissions control circuit, P0441 - EVAP incorrect purge, P0446 - EVAP vent control circuit) and P0141 - O2 heat circuit B1S2.

I found a copy of the FSM that I've been using for guidance (along with pulling up a whole lot of old threads from this forum), and have been spending my weekends going through the diagnostic section and trying to get everything up to snuff. I replaced the downstream O2 sensor with a new Denso sensor and found out that my VSV for EVAP is dead and stuck shut, I have a new

$37 Aisin VST-001 Bulk Vacuum Switch Valve - Green

Aisin VST-001 that should be here tomorrow.

I've got a situation that just started a few days ago though where I'm getting a cylinder 3 misfire and blinking MIL under load that only happens when I start it when the engine is warm. If I let the truck sit for a few hours (or less, depending on the trip) it runs just fine. Currently, the only codes being thrown are P0303 - Cylinder 3 misfire, and P0171 - System too Lean (Fuel Trim).

I've cleaned and tested the MAF sensor, replaced the spark plugs with a new set of NGK BKR5EYA–U, swapped coil #3 with #2 (no change in misfire), checked cold and hot resistance of the coils, and checked the ECM voltages.

I have yet to check compression, though it seems more of an electrical issue. I could drive for hours, the misfiring doesn't start until it is turned off and then on again. I'm also getting a throttle body and IAC gasket in tomorrow, so I'm planning on pulling and cleaning those and getting down to check and test out the injectors (where I'm thinking I'll probably find the issue) while that is out of the way.

Does anyone have any ideas besides a plugged/shot injector that I may be overlooking, or anything to test out/check? I have data logs from a 4-mile trip to the store (not misfiring) and back (misfiring) I recorded today with OBD Fusion with the enhanced PIDs that I've attached if anyone wants to look them over.

Thanks!

 

My long term fuel trim is also incredibly high (10 to mid 30s). I'm not sure if that has anything to do with the EVAP VSV being stuck shut, or if that is going to be a whole new issue to figure out. I wish I would've had a baseline reading before the misfire started to know if that has been an issue the whole time...

 

You are at the miles when fuel injectors start to fail. I recently had a similar problem with cylinder #2 on my 3.4 V6. The solenoid goes bad in the injector and only allows it to work when cold that’s probably why you throwing the lean code P0171 and the P0303.

Buy you a cheap stethoscope off Amazon get the engine warm until it misfires and compare the sound of the #3 injector to one that is not misfiring. A working injector will be clacking and the #3 if bad will have a faint tick totally different from the working injector.

 

https://a.co/d/2jR2gtY

 

Thanks, that's kind of what I was thinking. I checked the voltages for all of them at the ECM, and was able to check the resistance for #1 and #2 when the engine was cold and those were both in spec, but #3 and #4 I'll probably have to pull the throttle body to access. This is my only vehicle at the moment (I've been using my girlfriend's car when she isn't working the past few days), so I can't really have it out of commission long enough to send out the injectors to be cleaned and rebuilt. Should I replace them all with a set of OEM injectors, or are they considered something that's better to only change out when they need it?

 

I only changed out #2 injector with a new OEM at 265.00. I’m sure I will be regretting this probably sooner than later. If you can afford to replace all four of yours.

I haven’t bought from these people but I hear they have good injectors at an affordable price.

https://motorwestperformance.com/?srsltid=AfmBOoqSYyWtMe4ehLVZk_7EGaaFEbPdubYEHmBGIHVrM9R-DXSRKftW

Here’s another good source.

https://www.fiveomotorsport.com/199...999-04-tacoma-34l-6-cylinder-single-injector/

 

I am not saying this is your problem but it’s a good place to start diagnostics.

 

NEW fuel injectors: Toyota Tacoma 2.4 2RZ, 2.7 3RZ, 4-Runner (CA Only) OEM P/N: 23250-79135

 

Thanks for the input, I really appreciate it. I try not to just load up the parts cannon before I figure out the underlying issue when something goes wrong, and it helps to have an outside opinion or insight on things. I just ordered that stethoscope that should be here in a couple days, and I was planning on swapping out the fuel filter this week as well (the guy I bought it from had it for ~70k miles before I did and hadn't changed it out).

 

@O’Silver_Taco is a great source for advice on these engines he has probably forgot more than I will ever know.

 

Smart man that parts cannon can get expensive.

BTW welcome to TW!