2008 Tacoma bogs down intermittently

hey guys.. just bought a 2008 Tacoma v6 4X4 , 156k miles.. I have an issue where if I am driving it will bog down intermittently. It has happened on take off , on highway and I haven’t seen any rhyme or reason why it happens. If I am on the gas it’s like It Bogs down but if I take foot off gas and gun it , it takes off? I’ve changed plugs, cleaned throttle body and replaced MAF sensor. No codes are being thrown..any ideas? I’m thinking cat , fuel filter , fuel pump or maybe linkage from pedal .. help!

 

Well there is no pedal linkage so you can cross that out.

 

I would think all 3 of those would be a more constant issue. I think the cat would throw codes if it were clogged. The fuel pump/filter are thought to be somewhat crappy in these trucks, though you don't really read about a ton of issues(well, relative to issues like frame rust, drivetrain wobble, etc.); you might look into swapping the pump/filter out for a URD upgrade. I hear it's somewhat of an involved project, but you gain a much better fuel pump AND filter that is easily replaceable. I plan on doing this to mine when I get the chance. Just my two cents.

 

You are going to have to check fuel pressure and you are going to have to disconnect the cats and try to drive it. If it's easier try disconnecting the upstream o2 sensors and see if the problem improves even slightly but I would check fuel pressure first.

 

Check transmission fluid level

 

Try this for sure. My '05 had a "flat" spot or mild bog down in 3rd gear on a certain road around an uphill corner. I checked the fluid level and it came out 1 full at over filled ( my fault from a month or so ago). Corrected it and no more bog or flat spot.

 

So does the 08 v6 not have a tranny dipstick?

 

No, but there’s a procedure that’s not too hard (since you apparently can change plugs) that lets you check the level. Google it

 

My money is on a plugged cat. You get off the pedal and it bleeds some exhaust out, then you romp it and it takes a few seconds to pressure back up, but then you’re gutless again. It’ll likely throw a code eventually.

 

To rule it out since it happened to me. Check the brake switch behind the brake pedal. Make sure it's installed properly and hasn't worked it's way out or twisted. My truck would bog in similar situations until I put the switch back in right. Been fine ever since.

 

How will this create a bog down? I know I can do brake stands all day long with my '05, do the newer ones have a throttle cut out when the brake is applied?

 

I vaguely remember during the TPS recall debacle that Toyota claimed if any of the people in the accidents caused by “The stuck accelerator pedal” had press the brake pedal, the throttle would have cut out.

I can tell you that before the TPS recall on my 2010, every time I drove past a certain building, my throttle would stick. I could move the accelerator pedal all I wanted, but I would just keep going the same speed. Pressing the clutch or the break “unstick” the throttle and I would regain control. After they replaced the TPS, it never happened again. Driving past that same building would also make my radar detector go off.

Pressing the break probably is supposed to have some degree of impact on the throttle, but I don’t know for sure.

 

The recall for unintended acceleration. Punch the accelerator over a certain % and the brake at the same time, the computer cuts the accelerator. Guess your 05 has an open recall. Lol.

 

They did the throttle pedal mod with what looked like a chainsaw years ago. That's all. No throttle cut out on my truck.

 

Well, thanks guys for all the info . Had exhaust shop test cat and bingo. Glad I know what the problem is but not too happy about cost .. $1900 for new cat and muffler.. yikes .. but I’m hoping it’ll sound better and up the gas mileage a bit.

 

On my 2.7L I just cut the old cat out, and welded a universal cat in it’s place. $110+ tax. I found a manifold and cat combo for the 4.0 for under $400. Just pull the old manifold and bolt the new one on.

 

They cut my pedal(which never stuck), gave me new floor mats(the old ones never interfered with anything) and installed a new TPS(which had definitely been acting funny)