P0171, got to be an exhaust leak

[Doc2012]

Best way to check for exhaust leaks?
[MENTION=118207]midcoma[/MENTION] and I have done every test in the FSM for the MAF, O2 sensors, ECTS, injectors, etc etc.

My vacuum lines are good, everything is connected.

I've got to have an exhaust leak somewhere between the manifold and the upstream sensor.

Can't feel anything coming out of the flanges, but there HAS to be a leak somewhere.

Saw a guy on YouTube hook a shop vac up to his exhaust so it was pushing air into the system, and spraying it with soapy water. Might try that.

Anyone have any other suggestions?

 

[St Runner]

You could sea foam the engine, duct the exhaust so the it does not obscure everything and then check visually for leaks