Surging and dropping RPMs 2.7L

Hey all,

Ive been looking all over for someone with the same issues and I cant seem to find any. Anywho I have a 2012 2.7L 4x4 4 speed with 150K. I was driving through a pasture today and starting notice the trucks tach surging and dipping from 1000 RPM to 1400 with constant throttle pressure, confirmed on the road on even ground. It didnt do this in 4th gear only around 20mph or so in 3rd/ 2nd. Any thoughts? Idles fine. No MILs. Serviced 1,000 miles ago so oil level should be fine. Thanks for your input!

 

Could be many things. First thoughts are MAF or TPS. Have a scanner where you can view data?

 

I ran it through a scanner and nothings there. I ran some MAF cleaner through recently enough. I’ll bet it’s TPS, I hadn’t thought of that. Or maybe a vacuum line leak?

 

What kind of scanner are you using? Most allow you to view live data while driving. Should be able to see if the TPS has a bad spot in it just sitting still, slowly depress the pedal and the reading should go from 0-100% in conjunction with pedal position. Can do this with engine off so you aren't revving the engine. MAF you can watch flow rates for anomalies. Vacuum leak would show up in your fuel trim data if it is intermittent, then you will see the short term fuel trim changing around when you have problems. If it's constant, it will show up as a change in the long term.

 

I have a scangauge II, so its not that fancy. I will try reading the gauge with the TPS and scangauge, I know I have the TPS percent gauge, I didnt know it worked when in ACC. Thanks!