Odd Issue Bouncing RPM 300-500 RPM idle

[03Explorer4x4]

Hi, Ive owned my Explorer since new this is the first issue ive EVER had with the truck, The explorer just rolled over 130'000 Miles. Drove to the store this morning shut truck off went into store came back out started the truck up and the RPMS sat bewteen 300-500 and kind just bounched around there
i could drive the truck slowly as long as I didnt try to hammer the gas or it would stall right out and die, driving along you could feel the truck surging let off the gas and rpms would drop right down to 300-500 at driving speed
i limped the truck to the closest garage they brought the truck in and NO CODES they drove the truck and the problem wasnt there, Long story short they never charged me for looking at it as they couldnt find any issues

was just wondering if anyone has come across this issue? what was it?

My fuel filter is new engine was tuned up * plugs and wires air filter * at 100'000 miles. tank was full of gas, like i said never had any issues with the truck up till today heck I still have the original battery still in the truck LOL.

so ya low idle rpm 300-500 driving along it would surge like crazy and it jst wanted to die if you put the gas peddle to the floor it would die then be hard to re start, take it to mechanic and problem isnt there when he fires it up to bring into shop???

any ideas??

thanks
Dave

 

[The Rainmayker]

Bad gas perhaps? Did you fill up at a cheap off-brand place? I had the same exact scenario with a different vehicle, in end the cause was believed to be cheap gas purchased while on vacation.