So Explorer started surging bad tonight- going up a hill it almost cut out and wasn’t running solid-
got to where we were going and I put it in park and mashed the gas peddle to the floor to see if it would rev clear.
it did not rev past like 3000 rpm and wasn’t clean it would rev die rev die but not clear out

truck Has 15000 on it- limited v8

thoughts?

 

Wife told me last week she almost ran it out of fuel and it surged into gas station……..

ran fine today for a bit then after a bit it started acting up
at 45 it started surging and reving from 2500 to 1500 while steady peddle. I lifted off throttle and coasted a bit and then ok…..

not sure what to check

 

Most modern vehicles have a rev limiter that prevents someone from revving the engine past 3000 or 3500 rpms while in Park or Neutral, so that shouldn't be a cause for concern

Based on your description it sounds like your Explorer either has a misfire from the ignition system, a vacuum leak, or is being starved for fuel. Vehicles sold in the US since 1996 have a pretty good misfire detection system. Do you have a way to check for diagnostic codes? If you don't own a scan tool or code reader personally, is there an auto parts store nearby? Many will check for diagnostic codes at no charge. However, you want to find out what the precise code numbers are, not just get their verbal deciphering of the code. You may find something like P0171, P0174, or P030x where x is either a 0 or the number of the cylinder that is indicating a misfire.

If there are no diagnostic codes being reported, then if you have a fuel pressure tester, check the fuel pressure with Key On Engine Off (KOEO) and Key On Engine Running (KOER) to determine if the fuel pressure is within specification. If it is, or you don't have access to a fuel pressure tester, then you should carefully check under the hood for any damaged vacuum hoses as well as the intake air tubing for cracks or bad connections.

Let us know what you find and more suggestions can be offered.

-Rod

 

For engine speed to be changing like that, seems like the transmission has to be shifting or slipping, assuming you maintained a constant speed. What's the normal engine speed for 45 mph? What happens if you lock out OD and/or try it in 3rd gear?

Maybe you just got some bad gas. It's been known to happen. Buying gas under duress means you have to buy gas at the nearest station, which may not be a good station.

 

read codes with a Ancel AD310 and nothing stored or pending.
wife says she put 10 miles on it and it was fine.........
i dont have a fuel pressure tester so i guess i will look for one and look at the lines and try to put a couple miles on this thing