If you have documentation that the current issues manifested during the 90 day warranty, then I would say yes. But even if they first occured during the 90 warranty, you must first check to make sure that the failed components were in fact covered by the warranty. For example, if you warranty only covers Powertrain, then the warranty would cover the engine and transmission (and depending on the wordage, it may include or exclude axles). If your radiator fan quit, then it would not be covered by a powertrain warranty. If you are covered, and the dealer (I assume that it was a dealer, as no private party sale would likely include a warranty) refuses to honor the terms of the agreement, then you do have recourse. Depending on the limits of NV, you can sue in small claims court. Have the vehicle inspected by a few licensed repair shops, get a written quote on the repairs, and then sue in small claims for the average of the quotes. Don't be afraid to sue in small claims, you don't have to be a lawyer, it is very informal. Just make sure that you have all your paperwork in order, and make sure that you have at least 3 copies of everything. That way as you introduce your evidence, you can keep one copy in front of you, another is given to the judge, and another is given to the defendant.