truck missing at high rpm help

[02SE]

Unfortunately, without seeing, hearing, and driving the vehicle, or even hooking it up to a diagnostic machine while it's running in real time, to see how all of the systems are running, all of the helpful suggestions are just a guess.

You've replaced the easy things that could cause a misfire. I'd suggest taking it to an experienced Tech that can diagnose and fix the problem.

 

[blue dog]

After endless hours of checking wires and grounds and all the other crap i threw at this truck, today i decided to swap out the o2 sensor. First i just unplugged it and for what ever reason i decided to fire the truck up. She ran perfect. I took her for a drive while the o2 was unplugged and all good. Got back to the driveway and installed a new oem o2 sensor and start the truck back up. Immediately idled rough, took it around the block and it was back to misfiring. Came back home, installed the original o2 sensor and left her unplugged and the runner runs perfect. Riddle me this batman, how the hell does that work ?
Cleared all codes and will see what happens tomorrow.

 

[the great him]

when did you replace the o2? and with what brand? i went back and reread from the beginning and you make no mention of changing the o2 -before or after the problem started... if you replaced this before the issue started id say its a faulty o2 sensor that should be warrantied, but if you did this after the issue idk...

 

[blue dog]

O2 sensor was replaced about 4,000 miles ago. Anyway, the truck running well only lasted till this afternoon, she is back to backfiring and missing, but only at highway speeds. She has also started to idle rough until she warms up.

 

[the great him]

have you done/tried anything with the injectors, or looked for lose grounds?


also what brand o2 sensor did you use? what cylinder are you misfiring on now?

 

[LittleCaesar]

If I can remember the new o2 sensor was OEM as well. Did you see if the sensor # the parts guy gave you was the correct one?

I can't tell you have many times over the years I have gotten the wrong part the first time.

 

[blue dog]

Double checked the o2, was correct. oem denso unit. Checked all grounds. Have not checked injectors because the truck runs good/normal sometimes and at different rpm's, so i figure injectors is out.
Marked my coolant lever to see if there is any loss, will check again tomorrow.Could be a minute head gasket leak into cylinder 3
Truck ran like poo poo today, until tonight, she ran fine for 10 miles, then back to poo poo.
This one has me stumped
I believe this one is of the electrical nature, but i only play a mechanic on TV.
wonder if i found a ecm, if that is worth swapping out ?????
all in all this runner has treated me right and she has over 274,000 miles on her. But, i think it is time for a new ride. Got a line on a 2004 tacoma 4x4 5 speed with factory diff lock that has 106,000 original owner miles.
Kinda bummed, i had this thing in my mind about hitting 300,000 miles in this rig, but now, i just want something that runs ad drives reliably.
Thanks to all for the suggestions, i do appreciate it.
Cheers gentleman.

 

[5vzT4R]

I would say try swapping cylinder #3 fuel injector with a different cylinder fuel injector, but the 02 sensor situation has got me. Very strange how it ran fine un plugged.

 

[the great him]

I'm telling you its an injector problem... But you don't want to listen and want to tell me -us that its not so I'm done here. Just go sell your truck as a fixer upper that's a pos and has a bad motor idc done trying to help, you obviously know more about these trucks and motors than any of us. Good luck

 

[LittleCaesar]

Like the kid said you at least may want to take a cursory at the injectors, at least with using an ohm meter as well as unplugging them to see if there is a change in idle. I just helped a buddy change a PCM in a Jeep Cherokee that was throwing all sorts of codes, but it is a Jeep.

The Tacoma sounds nice; good luck with it if ya buy it.

 

[5vzT4R]

It only makes sence to swap cylinder #3 fuel injector with another cylinder that wouldn't cost you anything to test it, or use a ohm meter. Instead of buying a new ecm and throwing money at parts that could possibly be just fine.

 

[02SE]

I believe this one is of the electrical nature, but i only play a mechanic on TV.
wonder if i found a ecm, if that is worth swapping out ?????

I played a Master Tech in real life. Until I got tired of the games played by management towards service department employees, and got out to pursue other interests.

It could be any number of things. People throwing out guesses on the internet, can sometimes guess the problem correctly, and the problem will be fixed.

So, just to reiterate:

Unfortunately, without seeing, hearing, and driving the vehicle, or even hooking it up to a diagnostic machine while it's running in real time, to see how all of the systems are running, all of the helpful suggestions are just a guess.

You've replaced the easy things that could cause a misfire. I'd suggest taking it to an experienced Tech that can diagnose and fix the problem.

Good luck.

 

[SV_Dude]

[MENTION=87613]blue dog[/MENTION] [MENTION=60147]the kid[/MENTION]
You both need to chill out. Consider this a warning. We are all here to help eachother out. If one of you don't like the others advice or don't want to take some advice, then ignore it and move on.

 

[opie74]

Ive had coolant temp sensors go bad without tripping the engine light.