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Ivan, ASE Certified Master Technician
Category: GM
Satisfied Customers: 4871
Experience:  ASE Master Tech.20+ years exp. 9 years self employed. Participant on AutoLab Radio broadcast
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Where is the iat sensor for a 1991 GMC Sierra 2500 bare bones pickup

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Where is the iat sensor for a 1991 GMC Sierra 2500 bare bones pickup

HelloCustomer what size engine is in your GMC?


Your JA Expert,


Customer: replied 7 years ago.
Your truck does not use an IAC sensor. There are no provisions in the PCM nor does it show up on any electrical diagrams or location charts for your truck. That is why you are having trouble finding it.
Customer: replied 7 years ago.
I am installing a performence chip that specifies IAT MAF or AFM isolated to a 2 wire plug from slr Motorsports

Your truck uses a MAP sensor. If you would like, I'll tell you an easy way to add an IAT sensor to your truck to satisfy the chip. It is a simple process.

For installing an IAT sensor, it will only work if the system is looking for an input, if it alters the IAT signal into the PCM it will not work. This chip may not work for your application since they are referencing a MAF sensor. It sounds like it's meant for an OBD2 system when you have an OBD1 system.
Ivan and 4 other GM Specialists are ready to help you
Customer: replied 7 years ago.
the instructions say maf or afm sensor..any difference?
Your truck does not have either of those items, either. I really don't think this chip is compatible with your truck.