2003 Tacoma 3.4 v6 rough idle and no power !!

So I’m having this problem with my 3.4 pre runner auto. It has a rough idle all the time. Cold start and hot start and when coming to a stop. Truck has no power at all. Does this all the time. Feels like the gas pedal is dead u can floor it and the rpms only reach 4 and barely goes. Will do 50-60 on Highway but takes a while. And going up hills suck lol. Also my gas mileage is terrible !! Anyone have any ideas what I should check first ? No check engine lights on at the moment.

 

I'd still run a scan. Sounds like it's not getting enough fuel, but that's just a guess.

 

I wish it was fuel pump but done had one wjth bad fuel pump it just quit running all at once

 

MAF, I'm 99% sure. All the symptoms match your description.

 

So I unhooked it and engine died so its working right?

 

Not necessary. It's functioning but not providing actual measurement.

 

buy some MAF & Throttle body cleaner. Clean both of them up, and see if it improves. There are video's on you tube that will help you out.

 

yeah I had a similar experience when the MAF went bad on my old Prerunner 1st gen. New MAF sensor fixed it, but try cleaning yours first. Use MAF cleaner only, don't use generic electronics cleaner or carb cleaner on the MAF sensor.

Maybe see if you can swap MAFs with another 1st gen if you know of one, just to confirm. Sometimes cleaning them doesn't work if they're too far gone.

 

So I just noticed my intake isn’t hooked up to my breather box like it broke where it hooks up at. You think that would be causing it. It’s getting a lot of air right behind where the mass air flow sensor is

 

Yup that'll do it...unmetered air is getting into the system and causing it to run lean. I'm surprised you're not getting a lean code (P0171) from it, these trucks are sensitive to vacuum leaks. Probably a pending code I'd guess

At the very least it's part of the problem, I would get that fixed up and see where it stands

 

worth it to pull plugs and check those too. There are charts and pictures on the inter-webs that help use plugs to diagnose similar issues

 

Running these codes. I changed plugs but noticed my plug wire boot has a bad cut in it.

 

Hi all,

Did you ever end up with a solution for this? The symptoms seem identical to my issue - rough running, reduced power through all gears.

Sometimes when I start cold the behavior isn't there and the truck runs as normal, but I can feel the power start to go after it heats up and I hit ~35mph, then I can feel the power reduce and the rough running begins.

I cleaned the MAF, I guess next steps might cleaning the throttle body?

LMK if anyone has any suggestions - thanks!