96 Trooper

P1509 IAC- Idle Air Control code has appeared & has been replaced with NEW IAC device in compliance with the annoying check engine light. Then a code for the EGR valve has made its way to the dash indicator. Which has been replaced $150 dollars recent (part only). Now P1509 has plagued the Check Engine Light AGAIN. A gentleman at AUTOZONE suggested the warnings may be stemming from a defficient hose somewhere in the giant theme park of hoses that wrap the exterior surrounding both of these items (IAC/EGR) which in turn may trip the sensors to read abnormally. Hence, sending the wrong signals to the devices necessary to regulating the idle air flow. And trips the RETARDED light over and over again. How can the laiman (myself) work through this conundrum of circumstances. P.S. I am a writer/artist with minimal automotive

It would be probably less expensive and less aggravating to have a professional mechanic look at it. Try and find someone who is very knowledgable about Isuzus. I’ve found that sinister problems like this are typically common in certain makes, but can drive someone crazy who isn’t familiar with them.