1999 4runner SR5, 3.4L V-6, 4WD, 5-spd manual tranny.

The 4runner is having this issue, say I am on the highway doing 65 and go to pass a vehicle… leaving the trans. in 5th and trying to do this will result in some serious bucking… more so than normal w/ a standard trans.... the bucking is not specific to 5th gear.

The check engine is not on and I scanned the computer and there are no codes stored.

My thoughts are (in order of what I hope is wrong to what I fear is wrong.

-fuel filter
-fuel injector
-fuel pump
-clutch
-rear end

…seems like the first three options would trip a check engine code….

Any thoughts?

156k on the truck.

Engine RPM does not change (the engine does not race) when the bucking occurrs.

 

not the clutch, if it was the clutch you'd just rev the engine and not speed up...... not the rear end, you wouldn't buck you'd hear nasty noises.

sounds like a fuel hesitation problem. I'd start off by cleaning the maf and changing the fuel filter......

it could also be bad gas....unless it does this all the time

 

Sounds like you have a bad ignition coil, coil boot or spark plug.

James

 

Agree with James or vacumn leak or fuel. The computer doesnt throw codes right away--sometimes it has to happen for awhile for the computer to turn on the CEL.

But as i tell everybody--156k means it is time to start changing the sensors and wearable parts. TPS, MAF (Or Clean) Plugs, Wires, Coils, O2's, Send injectors out to be cleaned, pull the intake and clean it/them thoughly, Oils and Fluids (All), and hoses. Then put it back together and enjoy for another 100K miles.

Promise you that as long as there is no mechanical problem with the engine--you will see improvement in all areas. Also, do a leak down test to see what kind of health the engine is in.

 

IF you have an actual scan tool, I would read the misfire counts and see what cylinder(s) are acting up. You have to find out is it fuel or spark. Usually a bucking in 5th gear indicated an ignition problem. I would start with new coil boots and spark plugs. I do not know if they sell the coil boots separate but you need to call around and find out. When was the last time you change the plugs? Make sure when you pull the COP (coil on plug) that their is not oil in the tube, if their is change the valve cover gasket.

James

 

Not to change the subject--JAMEsD--i have family in Binghamton. I lived there for a short while also--mom was originally from there.

Ok back to the thread.

 

Did you go to school here? If you are ever back up this way, hit me up.

James