Why does my 1997 Lexus ES 300 surge after warming up and during slow acceleration?

What could cause my car to surge after replacing the timing chain, water pump, and various sensors?

After addressing misfire codes and performing a complete tune-up, my vehicle still surges at steady speeds. What should I check next?

 

Hello,

What specifically do you refer to as Surging? A video of the issue would be helpful.

What Sensors were replaced, and what Brand of replacement parts was used? There seems to be a surge of both Counterfeits, and just plain bad quality parts lately, so unless the Sensors are made by Denso and are purchased from a Trusted Source (aka not eBay or Amazon), I would strongly suggest to put the Original ones back in if they weren't explicitly faulty.

Seeing that the issue started after the Timing Belt replacement (it's a Belt-Driven Engine), it's only logical to assume that the mistake was made aligning the Timing Marks, if the Timing was never re-checked after the repair, I would suggest to pull the Upper Timing Cover off, which is relatively easy to do, and follow this guide to ensure that all the Timing Marks align as they should. You don't have to pull neither the Balancer Pulley, nor the Lower Timing Cover off to check Timing, as the "0" on the Pulley aligns perfectly with the Timing Mark on the Crankshaft .. or at least it should..

Hope this helps and best of luck!