Fuel trim ideas
09-11-2015, 05:38 PM
#1
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Fuel trim ideas
So I have been fighting this 5.4 for a while. Spark plugs replaced 3k ago and fuel filter. So the p0401 keeps coming up. Egr is functional and working. Muffler has rusted away and was cut off. My dads opinion is there is not enough gas in the system to make the light go off. With the scanner I can watch the trims start out around +10 and climb +20. I've cleaned the MAF and checked for vacuum leaks. Could the pcv valve be culprit. About the only thing we hadn't checked.
09-11-2015, 05:55 PM
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Forgot to mention that. My bad. Throttle body is clean. The exhaust pipe from the manifold to the egr is clear as well. Those were some of the simple things we started with. 98 5.4 vin code L.
09-11-2015, 08:24 PM
#4
The egr ports arent in the TB. they are in the elbow that the tb attaches too.