Misfire only after starting truck hot [2001 | 2.7L | Manual | 4WD]

Really puzzled on this one and trying to decide next steps, any thoughts appreciated!

~1000 miles ago I replaced my fuel pump (motor only) after it outright failed. After that the truck has been running great!

Over the last ~250 miles a very strange issue has come along. Whenever I start the truck once it’s warmed up (eg, running into a shop or grocery store) the engine shakes horribly and feels like it’s misfiring. No smell of gas from the tailpipe, no pops of unburnt fuel, only a slightly odd sound from the exhaust.

When starting cold, the truck runs like a dream as long as I keep it running. Spent ~4 hours driving mountain roads, hauling trees, and four wheeling with no issue because I left the truck running the entire time even for ~15 minute periods of idle.

The issue only occurs after the truck has sat for more than ~1 minute while hot upon restart. If I turn it off hot and IMMEDIATELY turn it back on, no issues to speak of.

Only once have I driven it with this issue and had it resolve while driving. Getting up to ~60mph (slowly) and holding for a few minutes the engine came back to full life and had no issues until parked. It then started just fine.

No engine code no matter how long the issue persists.

Mileage: 292,000

So far I have tried checking each coil by removing the lead while running and it kills the engine removing spark from any single cylinder.

I also bought a new coil and swapped each pack with no change.

This makes me think fuel is an issue, but puzzled as to what exactly would cause this symptom.

Any help appreciated!

 

I once had these symptoms be a head gasket. It put enough coolant in the one cylinder that it quenched it out until it cleared out and started firing again.

 

I would be confused if it was head gasket due to my coolant level remaining unchanged for the last month as well as the fact that there is no issue with cold starts. I could be wrong but I imagine when the gasket gets cold and contracts that would be the greatest opportunity for coolant seep that would cause an issue with cold starts. Truck starts like a dream cold.

As well, no white smoke from the exhaust that I would consider a tell tale sign. Did an oil change yesterday and it was clean as could be!

Not completely ruling it out, but to my knowledge head gasket seems unlikely with the current symptoms. More often than not I cannot drive out the issue and it persists until I limp it home (once over 10 miles).

 

I’m with you and hope it’s not that also. If you aren’t losing coolant, you can probably rule it out. Might do compression and leak down checks though, just to see if anything gives a oddball result.

 

Wheaty
Carve some time out of your schedule
Search “hot no start”
Get ready to go down the rabbit hole
(For good reason)
There are simple $20 fixes(coolant temperature sensor)and kinda expensive ones(fuel injectors)

my issue was injectors
No issues now for me now!

In addition
Don’t buy $60 eBay injectors like I did
Ugh
Search MotorWest in CA
$125 to RM your OE(like I did being referred by many members here)
GL

 

I came across this thread because I’m experiencing the exact same issues. Smooth idle when cold, rough idle when hot.

Codes show misfiring and running lean.

 

I can vouch for the fuel injector fix. Had the same cold start= smooth running, hot start = #2 misfire consistently. Pulled the 4 injectors and took to Motorwest Performance in Los Angeles (you can also ship them there) and got them rebuilt. #2 injector was bad upon testing, gave me a "new" rebuilt OEM, out the door for $115. Starts and runs great, hot or cold.

 

Here to complete the saga, the issue has finally been fixed. I took it to a shop and they replaced the #1 injector and said it HELPED but did not completely fix the problem. This was a huge miscommunication.

From there I took the car back and told them to keep their injector. From there I did the following -

Fuel pressure was slightly low both deadhead and T in test

Then I replaced the fuel filter. This made no difference but glad I did it, that thing was disgusting. Not an easy job but much easier when taking off the drivers side tire.

Then I replaced the fuel pump. I had done this recently but replaced the master pro with an Import Direct for slightly more peace of mind.

Then I had no readout from my upstream O2 sensor so that was replaced. Barely got away without breaking the rusty studs but got'er and subsequently got a lean condition from the misfire.

Then I then got an EGR code. I replaced the EGR gaskets, bench tested and cleaned the EGR, no more code. No fix to the overall problem.

Then I then replaced the FPR, no change to the overall condition.

Then I then tested a new MAF after seeing a bad ratio when it came to g/s. No change

Then made it back to the REAL PROBLEM THAT I SHOULD HAVE DIAGNOSED SOONER. Putting a multimeter to each fuel injector, number 2, 3, and 4 all read just fine for resistance.

Fuel Injector #1? DEAD. DUH. At least it's easy to get to.

Now the real journey, finding the correct fuel injector. I needed this running now because the condition had gotten worse (rough condition at all times of running, not just hot start. Every shop in my area told me they had the part but upon inspection they were different units. No seal on the tip, no chance of them sealing and working.

Frustrated by the idea of a $160 part that may or may not work (most likely not) I went and purchased a full set of remanufactured injectors from Rock Auto. These are the parts I purchased. Upon arrival I received the EXACT SAME incorrect injectors, these are what they looked like:


I sent these pictures to Rock Auto and they said they should work just fine. How? They're a different length and attachment?! Thinking I was just being an idiot and apparently these are OEM remanufactured replacement, I installed one injector.

It proceeded to SPRAY FUEL LIKE A PISSING DOG from the mounting point to the rail. What the hell!

Then I went on the hunt. After being burned I wanted an injector that at least looked the same as mine, like yesterday. I need this truck to be running. After shopping around and being impatient,

$70 JDMON Fuel Injectors Compatible with Toyota Tacoma 2.4L 2.7L 1999-20044Runner 2.7L 1998-2000 Replace 23250-75080 4Pcs

I bought these from Amazon. I know I know, Amazon parts, but I was getting desperate here.

I replaced number one injector and IT WORKS. THE PUPPY PURRS.

Planning to find a proper OEM remanufacture in the future but this is my tale. Thanks for all of you that suggested injector, I wish I had listened to you sooner.

See you in the next thread,

-Wheaty

 

There is a saying... quality is long remembered soon after price is forgot.