HELP - Engine Bogging down

[carnepo]

I've done a lot of searches and no responses make since.

I have a 2003 v8 4runner sport.

Recent Service: two weekends ago I changed my oil, went to a synthetic and changed my transmission fluid and filter.

I was driving home from work the other day and my 4runner jerked, kinda like an unexpected shift(never had that happen before) and I let off the gas for a second then continued to press the gas again and it barely accelerated. kinda like a safe/limp mode or something, I put it in neutral revved it up and it climbed very slow, not normal at all. I pulled in the gas station, no light or warning or anything. turned it off, called a friend to describe the issue and see if he had any insight.. got back in turned it on and it revved normal put it in drive and off I go as normal. While its driving normal I hear a whining sound when I accelerate, (normal acceleration) kinda like a power steering pomp kinda whine. but Idling and revving at a stop it sounds normal.

I have an drive right chip I have I had plugged in after the fact and it did not throw any codes.

on the way home from the gym tonight I was at the stop light and it jerked and when in the bogging state again. I pulled over, turned it off and turned it back on and it drove normal home.

I'm sure this is some sort of a safe mode because something is wrong, but I cant figure it out and no one I know can help.

Any help would be greatly appreciated.

thank you

 

[zonianbrat]

I could be wrong but I would think any time the truck purposely goes into a safe/limp mode that some code would be thrown. I'd stop by an autozone and have them scan for codes just in case. When was the last time you changed plugs? I'd also check the wires where they plug into the coil and make sure they are not bent in there. Other than that I would check the maf sensor, clean the throttle body and maybe seafoam it. Good luck.

 

[imagemaker]

Man, if you ever did find a solution, Id love to hear it. I have a 2000 4runner 3.4 doing the same thing! Replaced air box,(potential stripped screw on the MAS) replaced MAS, Replaced TPS, replaced IAC, Replaced ECT, Replaced brake booster ( as per Dealer diagnosis) , checked vacuum lines for breaks. New plugs. No codes. Been to 4 shops, all the incorrect diagnosis. The problem is exactly the same and has not presented itself differently after each repair.
Runs fine on start up. As it approaches normal operating pressure, it will seem to lose power. If you come to a stop and accelerate it bogs down, back fires through the air box. Does the same thing if restarted after 30 minutes. When the issue occurs , if you pull over and restart the vehicle it will return to normal operation
NY HELP IS MUCH APPRECIATED!

 

[scw1991]

Had a same scenario with a GM car years ago. Turned out to be a clogged catalytic converter

 

[Supersonic]

Look and try to clean all your ground connections, and both battery terminals.

Similar to this, only I couldn't find a link to 4th gens;

http://www.toyota-4runner.org/3rd-g...wiring-ugrade-3rd-gen-toyota-4runner-how.html

Here's a couple more that may offer some insight,

http://www.toyota-4runner.org/4th-gen-t4rs/242257-help-no-start-no-crank-issue-2.html

http://www.toyota-4runner.org/4th-gen-t4rs/136573-mystery-electrical-problem.html

You can try this search anywhere and sometimes other Toyota trucks have similar issues and hopefully solutions too, just copy and paste the whole line into your search engine;

site:http://www.toyota-4runner.org/ ground connections

Then you can copy/paste another substitute link for the site;

Tacoma 2nd Generation (2005-2015) - Toyota Nation Forum : Toyota Car and Truck Forums

 

[Atlanta_man]

I had a bad ground to the ecu on a 96 Pontiac. Took the shop a week to isolate it.
Crazy engine speed and power variation.