My 88 duke was getting 28 MPG normally then it went to 21 with an occasional SES code 44 at idle in a stop light.Code 44 => Lean exhaust, O2 measured too low
I found a small crack in the exhaust manifold, I mean small. Hairline! I thought no, really. But yes, that was it.
I went to the local LKQ and they had one 1989 Chevy Celebrity with a Tech4 in it. The manifold is an exact fit.
My gas mileage is now back to 28 MPG @ 70MPH highway w/an automatic.
Project Genisis Lo Budget 3800SC swap
email@example.com MPH Intense-Racing 1.9 rockers, 3" exhaust, 3.4 pulley, ZZP tune and 18 year old tires.
88 Coupe under construction
88 formula 3.4L 4t60 swap SOLD