Ihave been trying to get rid of the pesky P0171 and P0174 code. I Saw a recommendation on this site about putting RTV around the gasket between the Throttle body and Intake Manifold. So I took the throttle bottle off, cleaned it real good with carb cleaner, put some RTV around both sides of the gasket, let it set for about a hour, then assembled. Some of the RTV pushed in. I pushed open the the throttle flap, stuffed a clean lint free rag into the intake and took a exacto knife and remove most of excess. I could only see some minuscule pieces of RTV, nothing that should affect anything if it gets pulled into the manifold.

I then put a bottle of SeaFoam spray into the throttle bottle while revving to 2k RPM as the bottle instructed and then let sit for about 15 minutes with the engine not running.

Drove it around for a while. It smoked as usual. Then drove it to meet my son, about 35 miles. No codes. YES.

Then he was driving it to Ft. Rucker and calls me telling me the P0171 and P0174 showed back up joined by P0420 and P0116.

Cleared the codes, but the P0116 keeps coming back. Had him "CAREFULLY" check the coolant reservoir and he said he didn't see coolant there, but could look from the side of the reservoir and see there was some in it.

Any ideas?

 

There are markings on the coolant take for level at hot or cold, make sure he checks those. What does the temperature gauge read?

 

He told me that the temp gauge stayed right in the middle where it belongs,

 

Latest update. Without doing anything other than topping off the expansion tank, the 420 and 116 codes have seemed to go away.

Now back to the 171 and 174 codes.

 

That really makes no sense unless it was wicked low and the low coolant sensor was broke.

 

Don't know what to say. Those two codes are gone now