I usually get my engine bay air pressured, not a fan of water pressuring, I believe it can trigger malfunctions in a long term. My friend had a Vitz 2005, he had his engine bay washed by a mechanic and the other day, his car was jerking between gear changes, because the water somehow got inside the computer. It was never repaired, he sold the car in the end with loss.
Sorry if I dropped a bombshell, everyone experiences their things differently. I just stated my honest opinion. Thanks.