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Running lean

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Old Mar 22, 2025 | 12:38 PM
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Running lean

I've been getting a check engine light ever since I got my '04 a little over a year ago. A while back, one of the O2 sensors blew out. That stopped the CEL for a bit but now I'm getting a lean code for both banks. Now, on my Dodge, my Mazda and my Oldsmobile, I can trace that down. Where would the collective suggest I look on this puppy. It's got the 5.4 16 valve engine. It runs okay, but I don't like to leave the CEL on in case another code pops up.
 
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Old Mar 22, 2025 | 03:12 PM
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A smoke test is the best way to find the vacuum leak.
The typical culprits are the PCV rubber elbow and the rubber grommet connection at the back of the intake manifold that the PCV pipe connects into.
Use a bright flashlight to inspect everything.

Mechanics Smoke Machine on Amazon Mechanics Smoke Machine on Amazon
 
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Old Mar 22, 2025 | 06:54 PM
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Originally Posted by Hamfisted
A smoke test is the best way to find the vacuum leak.
The typical culprits are the PCV rubber elbow and the rubber grommet connection at the back of the intake manifold that the PCV pipe connects into.
Use a bright flashlight to inspect everything.

Mechanics Smoke Machine on Amazon

I'll look into that. My Dodge had a similar issue but it's set up different. That was a home made gasket I made to get it back in service. I can probably borrow a smoke machine from a friend. He's retired like I am but he ran a shop long after I closed mine. (1984 in my case. I made more money with less hassle working in a factory.) The bad rubber part might explain the once in a while smell of fuel.
 
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