Q: How do I replace the fuel pu on a 1990 Lexus es250

On this vehicle, the fuel tank has to be completely removed from the vehicle to access the fuel pump. The fuel pump is held in a retainer that is mounted in a large access hole at the top of the tank and held on with about 8 small machine screws. There is a seal that is critical. Unfortunately, due to the age of the vehicle, unless you live in a very low humidity area of the southwest for example, you might end up replacing the tank as well and all of the metal piping at the top, including all the EVAP lines, due to the inevitable corrosion that builds up over decades. Usually, those lines are a leaking mess after about 15 years. Of course, the tank band straps may be corroded as well and not re-usable. ALL rubber parts must be discarded and replaced, otherwise you will have leaks. It’s doable, I have done it on this specific vehicle, but to do it right and make it a long lasting permanent repair without leaks, IF there is corrosion you essentially have to replace everything. Work like this on a 27 year old car is basically restoration work and not just a "simple" repair. In any event, if you desire that a certified Mechanic work hand in hand with you on this, help you with likely custom fuel line fabrication and get it all installed to perfection, please simply request fuel pump replacement service and the responding certified mechanic will get you squared away. Please let us know if you have additional concerns or questions.