Intermittent hesitation issue

Hello all,

I've just joined TW in regards to the subject of this thread. My 2008 4D LB TRD Sport has an intermittent hesitation problem that started several weeks ago at 91k. It occurs during both acceleration and steady driving conditions, and is best described as exactly what happens when you take your foot off the accelerator pedal, except you're not. The truck simply starts slowing down and the engine rpms drop. There is no perceivable engine skip, abnormal noise or vibration, and thus far, "recovery" from the hesitation is accomplished by applying additional pressure to the pedal. The time it takes to "recover" varies somewhat but at most takes only a few seconds. When the hesitation occurs while cruise control is engaged, it causes the control to disengage. No warning lights have ever displayed before, during or after any of the dozens of times this issue has occurred. The truck was taken to the shop for scheduled maintenance (spark plug replacement, injector and K&N air filter cleaning) a week after the issue surfaced, but no codes were reported during this visit and the problem has remained. The truck is now back in the shop and while the mechanic has not been able to replicate the issue driving it to and from the shop, one code involving a fuel pump sensor has been recorded. If anyone on this forum has any suggestions regarding troubleshooting/resolving this issue, your assistance is both requested and greatly appreciated.

With my thanks,

John aka kadman59

 

Sounds fuel related.

 

Well, if you're using a well oiled K&N filter I'd replace it with a stock type paper filter (because the MAF wire is now covered in oil) then spray the living shit out of the MAF sensor with the correct cleaner and take it from there. Sorry, just noticed possible fuel problem. Carry on.

 

Sound like symptoms of a malfunctioning fuel pump. Keep us posted on what you find out.

 

Fuel pump possibly.

 

Might also be a bad throttle position sensor.

Check this link and see if symptoms are similar to yours:
http://www.buzzle.com/articles/symptoms-of-a-bad-throttle-position-sensor.html

Good luck and keep us posted...

 

I'm meeting the mechanic tomorrow morning and I'll post an update afterwards. Thank you all for the numerous posts and suggestions...john

 

My mechanic drove my truck a full week and it didn't hesitate once. The DTC reported one code P0230 involving the fuel pump on the day I took the truck to the shop...that was the last day I experienced the hesitation. There was one event in hindsight that occurred prior to the hesitation issue, that being my driving until the low fuel light came on. This was perhaps only the 3rd or 4th time in 7 years I've done this...with the fill up taking almost 19 gallons, only a gallon was left in the tank. Perhaps the fuel pump sucked something other than gas?

 

Sounds like a plausible cause. Hope it doesn't show up again.

 

Could have just had a bad tank of gas.