2014 pre runner ss engine hesitation,getting worse!

Hey all,
I'm new here, I joined up to see if any one could enlighten me on a problem that started about a week ago: once the truck is warmed up, it hesitates intermittently, getting worse as the day progresses, some days, it doesn't do it at all, today was really bad, I was driving 70mph when it just started bucking like an angry mule on crack! Not a good feeling in rush hour traffic! If I feather the gas, it seems to settle down for a bit, but then start up again20/30 mins later. I drive for a living, averaging 2/300 miles per day, I thought maybe it might be the gas, I usually get Exxon or texaco 87 octane. I've tried sea foam,stp fuel injector cleaner. It seems like a fuel issue, but could it be a sensor? I bought the truck used with 30,000 miles, it now has 50,000. Any ideas/ thoughts would be greatly appreciated! I might add, this is my 5th Tacoma and I've never had this issue before. Cheers!

 

What's your general location - Hot or cold weather?? Also, are you sure your Temp gauge is correct? (+ Check Coolant level / contamination/etc. ) My First Guess would have been the Fuel - but you checked that. I'm thinking temperature. Runs OK Cold - Get Hot and runs crappy, etc. Eng Temp ? Fuel line(s) to close to the exhaust (Vaporization of fuel and screwing up the mix) . etc.

Let us know what you find please ....

 

I know sometimes the fuel in the area can play a significant role in the performance of your engine. Do you fill up at the same service stations? Try sticking to one service station (Shell, BP, Exxon, etc.) and see if that'll help. Secondly, don't add sea foam and fuel additives in with your fuel. A lot of people on here claim that ever since they added the additive their truck hasn't performed the same. I'm not sure if it has to do with the internal fuel pump or what. Just stick with the same service station and maybe switch to a different grade fuel (contains little to no ethanol) on the next few fill ups. Report back after going through two to three tanks.

 

Thanks, guys, I'll try both suggestions and report back in a couple of days, cheers! @Canufixit : I'm in Austin Tx, very hot climate!

 

Your Issues seems to lead to temp and or time. Your Thermostat keeps our cold hot AND Cool. During warm up it's closed. When Hot it's open. It also will open and close to keep a constant temp. IF it's Stuck at some position it affects allowing the engine to maintain a constant temp. Check temp/gauge. If you do not find any other issues , The Stat is easy enough to change and cheap.

Oh Yeah - check for codes as well.

 

Sounds like bad gas

 

Inspect EGR Valve and R&R if nesessary, Clean MAP Sensor and all air intake system !May be one or both ?

 

Have the spark plugs ever been changed? The 4.0L engine uses conventional plugs that should be changed each 25k to 30k miles; the COP ignition will fire them to 50k or even more, however as the gaps open up ignition timing retards a bit as the larger gap takes longer to ionise, and flame origin and propogation change--this can lead to the sort of speed/load related misfiring you reported...

 

There is no EGR Valve.

 

There is no map sensor either. Clean the MAF sensor, these engines are very sensitive to a dirty MAF