Reman 1997 Chevy 5.0 bad gas mileage

155

Asked by Johnathan May 20, 2014 at 12:17 PM about the 1997 Chevrolet C/K 1500 Cheyenne Extended Cab 4WD

Question type: General

I just had my mechanic install a Jasper remanufactured Engine in my 97 Silverado 2wd. I
just did a direct changeout (same size engine) 5.0 to 5.0. While this was being done I sent
my ECU out to be "tuned". With my old engine I was able to achieve 15 mpg average and
at its worst at the end we were looking at 13mpg. I now have about 5000 miles on the
reman engine and I havent got any better than 11.5 mpg since the changeout. Any ideas?
Could the tune be my culprit?  I also have a K&N intake, 3" catback exhaust, and a 3
chamber flowmaster. All of these I had for 5 years before I changed the engine. I also had
a new cat installed after the engine changeout too. Any help would be awesome! At this
point I can't afford to keep my truck or to get rid of it.

5 Answers

155

Yea everything is good. Having ac problems all of a sudden now. Could my ecu be bad?

60,305

check your fuel pressure/leakdown rate. Its a vortec engine with the spider injectors. The fuel pressure regulator is a known problem to fail and start leaking a little. Early sign is poor fuel economy. Just a thought, do you know what year 5.0 you swapped to? I'm wondering the cam it has

2 people found this helpful.
155

I have no idea what year they changed it out with. I will ask my mechanic to check the fuel pressure stuff as I do not have a Guage or knowledge to do so. Thank you for your help!

2,955

check your ecu the ac system works thru the ecu if your ac is malfunctioning is probably a good sign that theres an internal ecu issue I work on this models all the time goodluck godbless

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