I know this is probably a shot in the dark & I know should be getting my car scanned to find any codes, but I just ordered a scanner & it won't be here for a few days (hopefully), so I'm hoping someone can help in the meantime. But here's the rundown...

I went on a road trip back to Vegas LDW (live in MT now) & I figured while I was there, I would have Lexus take care of some recalls (VVT & the fuel pressure sensor). While there, they found an oil leak from the timing cover & said my water pump could use a replacement. Considering I have a full coverage ext. warranty on the car, I wound up leaving my car with them for a couple of weeks. Figured I'd let them do the $4300 worth of work since where I live, there is no Lexus dealer close, serious P.I.T.A

Anyway, I just went back to Vegas last wknd to pick my car up & drove it the 1200 miles back home. Car did great! But now, as of yesterday, I noticed as I would take my foot off the gas, the RPM's would fluctuate like CRAZY! Jumping between 500-1200, almost as if the needle was loose, that's how quick it kept jumping. I'd put my foot back on the gas & it would be fine. And while idling/stopped or when first starting my car, I now notice that it's idling higher than before, at about 1000 RPMs. It doesn't shake or wobble, just the RPMs jump & since I have an exhaust on the car, it makes it easier for me to hear it jumping. It's almost as if I'm pumping the gas pedal.

My dad is a mechanic, but for Dodge/Jeep & doesn't have a clue what could be stemming this so we just ordered a scanner in hopes of pulling some codes. And of course, now I'm thinking maybe something was goofed or missed with the work I just had done. I tried calling the service manager back at Lexus to see if he could at least give us an idea, but he hasn't called back yet, go figure.

So has anyone ever heard of this happening or have any inclination what could be causing this? I know it's hard to say without any codes to give out, I'll have to update this once I get the scanner, but I'm kind of stuck right now

 

I find it weird that your dad is a mechanic without a scanner.

I literally have 5 scanners + a Techstream cable.

I may be wrong, but I feel like there's been other that had similar issues after one of the recalls. I would try and search for that and go from there.

 

Disconnect the battery for 20 minutes to force the car to re-learn everything. Report back with your results.