2005 Tacoma whoas

D

dave

Member
I have a 2005 Tacoma double cab long bed with v6 4 liter 96,000 miles. Truck has always run smooth and strong up until a few months ago.

The truck on level or slight decline at around 40 mph and at 1000 to 1200 rpms engine suddenly looses a few 100 rpms almost feels like wind is hitting the truck from front a sort of pulsing, it also has a buzz in the the gas peddle that is hard to describe especially noticeable when climbing a hill or accelerating that buzz has been there for two years.

When you rev the engine slightly while idling seems that the engine should smooth out but actually gets rougher or shakes more than at idle.
It also seems like it has lost power. I used to have a boat that weighed about 2000 lbs and the truck towed it like there was nothing there. We recently got another boat about the same weight and truck seems to labor and shift a lot.

I recently changed the plugs and filter but that made no difference. Also added and enzyme to the gas for ethanol buildup also made no change.

Brakes are all good with no binding , all wheels turn freely when when checked while truck was jacked up. No idiot lights are on. Two years ago I had all fluids in transmission replaced and recently checked all levels. Drive shaft is greased. Only thing I noticed was the rear diff. clunks when you manually turn drive shaft back and forth.
I don't have a clue what to look at next any suggestions that I can do ...can't afford to take to dealer right now? Dave
 
The Mass Airflow(MAF) sensor is in the intake tube just under the plastic engine cover. It reads how much air is going into the engine so the engine computer knows how much fuel to inject into the cylinders.

CRC is just a brand. Think brake clean in a can but this spray is specific for MAF sensors. Don't use brake clean.
 
I would recommend not using carb cleaner. Some sensors have a coating that can be removed by carb cleaner or brake cleaner. Removing the coating will destroy your sensor. Some throttle bodies also have a coating.
 
Thanks , I will try that next......I did clean the throttle bodies with carb cleaner from Napa( that said it is safe for throttle bodies)...could that have damaged the sensor?
 
A co worker of mine was just telling me yesterday that his 01 at about that same mileage had a similar sounding issue. Turned out to be a fuel issue which I think he said was the fuel control module. Said it was something like $500 to have it fixed, which I think that was at the dealer. What ever he said it was, it wasn't getting enough fuel and ran rough. I know his is a totally different truck/engine but thought maybe it's a common problem and could possibly help you to diagnose. Good luck!
 
I'm back, tried cleaning the MAF but it didn't change. After I did it I didn't drive it but let it idle until warm then gradually pushed the gas peddle until around 1000 to 1500 this is where it starts making the engine roughest. Usually when you increase RPMS the engine should run smoother????? So I tried to hold it at 1200 rpms and it will fluxuate up and down less than 100 rpms. If you rev it it hesitates a little also. Should I replace the MAF next...any suggestions. I am supposed to be towing the boat to Maine next week to live and am nervous about it being something bad. What about the catalytic converters...I recently replaced the muffler all OEM?

Drove it later still seems rough and lower power
 
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What plugs were in it and what did you replace them with? The ignition system on the 4.0 V6 works best with OEM copper plugs.
 
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The cats would be a good thing to check, I've seen it some many times before that the comb inside the cat breaks down and causes alot of back pressure
 
Sounds like you might wanna try checking your coil packs. Your coil packs are attached to your plugs. The V6 4.0L has separate coil packs for each of the spark plugs. Start your engine and pull each coil pack off, one at a time until you get to one where there is no change in the way your truck is running. When you get to that coil pack, thats your bad coil pack.

Now there might be a better way to check to see if your coil packs are good, but this is the only way I know. Good luck and let us know how it goes...
 
When was the last time the spark plugs were changed?





Edit: I missed whippers post about the plugs. :shifty:
 
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It's got to be electrical. So you should start with eliminating things that you know it's not going to be. Then when your done eliminating stuff, I guarantee you'll be left with something electrical.
 
Thanks for the many responses, The plugs were changed two weeks ago (Denso) hoping that was the problem, I put in NGK iridium.

When I check the coils can I just disconnect the connector or do I need to pull the whole cap off the plug. This isn't going to cause any damage too the system right????

I also used a Throttle body cleaner from NAPA couple weeks ago maybe I didn't do it right (running bad before I did that).
 
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OK, removed each spark coil , one at time, each made it run rougher so its not that. However, it exaggerated what is going on. So it acts like one cylinder is not running although not the case.

What is the best way to clean the throttle bodies....I simply sprayed into the air intake and wiped clean the best I could?
 
What you wanna do is unholy the plastic cover that says "vet" on it. It has 2 bolts 10mm. Then unbolt the air filter assembly. It also has 2 10mm bolts, and you'll also have to unplug 2 wiring harnesses, the one to your MAF and the one going to your throttle body. Then take out, or move over the box assembly that holds your air filter ( you'll have to unscrew the clamp that holds the air box onto your throttle body). At that point you should be able to see your butterfly inside the throttle body. There's probably a lot of black stuff around it, so what I do is just spray a little carb cleaner around the butterfly and quickly wipe away the black stuff, then I'll spray the carb cleaner around the towel I'm using. (i try to use a rag that's dust free, or use the blue shop paper towels) then I'll quickly use one finger to hold the butterfly open and wipe the edges of the butterfly off clean. Sometimes I'll unholy the 4 10mm bolts that hold the throttle body on so I can access the other side of the throttle body. I JUST make sure I GET all the black stuff off and just make sure your not man handling the throttle body or any of it's internal parts. And use the carb cleaner sparingly. You don't wanna spray a whole bunch of it past the butterfly inside so that your engine has to burn it out. I did mine just yesterday and everything went great. The only thing other than what I outlines out here for you I had to do was disconnect the battery, then reconnect it so the computer could reset itself.. Hope this helps.
 
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