Hi Guys,

I have a 1997 Suburban that I would like to start doing small repairs on. When examining the engine, on the driver's side, I saw the item circled in yellow in the center of both attached photos (regular and close-up). It seems to be screwed into the engine, with a boot on the other side.

 

I believe that's the coolant sensor for the dash gauge, vs the one on top by thermostat that talks to the computer

 

That is in fact the coolant temp sender for the gauge. As @Rednucleus said, the one at the top of engine at the intake manifold close to the thermostat housing, is the sensor for the computer.

 

Thanks, rednucleus and PNW NBS Z71 . So, if my 97 Suburban starts up quick when cold, but takes longer to start when warmed up, which one of these two sensors might be causing the problem?

 

The circled one only runs your gauge and has no effect on engine performance

 

Your symptom is one of a possible leaky injector. Cold motor likes extra fuel, hot motor not so much. Try stepping on the gas pedal when hot starting and see if it improves. If so run a couple tanks of a good injector cleaner like Techron or one with PEA in it and see if it helps.
I had to change the spider injector setup in my old '99 Yukon for a leaky injector.

 

What @Rednucleus just said. But, that sensor may not be the actual cause of the warm start problem but would be a very inexpensive attempt to fix. This one is at RA for $31: https://www.rockauto.com/en/moreinfo...03063&jsn=2584.

It is the OE one. You can get less expensive aftermarket ones and even $10 less AC Delco one but I always defer to OE if available.

These engines also had problems with the fuel injection systems, SPIDERS, over the years.