Needless to say it's cold here in the San Antonio area too @ 20-24 degrees. Dropping into the single digits as I type - at night anyway. Days will be in the teens -records, all! Truck has been sitting in the N wind for the last 3 or 4 days. It was iced over but I got in to start it. Started fine. Let it run for 30 mins. didn't even melt the ice on the windows completely even thoughn the heater works fine. NP It was warmed up. I heard an "off beat" idle and got in to run the revs up a bit but it won't go much past 3K or so (3200?) and then intermittingly - off and on - big lag till the rpms drop - then back up to 3K.
It ran fine Thursday. wt? Back gas? Electrical? Tom Foolerlery? I can't go anywhere anyway because the roads are iced over. Drivers are actually turning around and going back - just saw one as I was coming back to the house. It's weird I think. Is this something common? The truck was a Minnesota fleet truck for 80K, then in private, uncaring hands for K in Okla., then I bought it from a good dealer - fixed a couple things - np after that until today.
Thanks for any suggestions.

I SHOULD HAVBE JUST CHECKED THE FORUMS AFTER TYPING THE QUESTION- IT WAS ALL SPELLED OUT, AND MORE! WOW- GREAT SITE!!

 

When automatic is in Park or Neutral or manual has clutch pedal down, OR speedometer is at 0mph on either, the engine computer has a REV Limiter set at about 3,000rpm

There is also a SPEED limiter, set for about 90-95mph