Hello Lads,
I recently bought a 2002 ZR2 with 4.3 engine 162K on it from the original owner in his 60"s that really took good care of the car, I have a pile of repair receipts. He put in a crate engine 30K ago and a rebuilt transmission 20K ago. When I bought it owner reported getting 17 MPG combined. The car runs great starts right up idle is at 625 RPM or so, No pops, backfires, step hard on the gas and it is gone!
Since I got it I was getting 12 MPG in city driving, I put in a new air filter, not an oil bath type, replaced a broken vacuum line that went from intake manifold to a T that goes to the charcoal canister I also put in a new PCV valve, Now I am getting like 8 or 9 MPG! No check engine light, and a hand held scanner says there are no codes present or stored from engine.
I am going mad and broke filling the tank. I can find no gas leaks, no smell of gas in engine compartment, and only a slight rich smell in the exhaust. There is no EGR valve on this model. It had new plugs, wires and distributor cap and rotor at the engine swap. The fuel filter looks almost new, with no mud or stains on it.
I went to two shops and a Dealer and explained the situation, I got two "it beats me" and we could do a $450.00 tune up but can't promise anything since it isn't throwing codes. I am thinging of replacing the Mass air valve to see if that has a difference other than that I am stumped,
If anyone out there can help, brother please speak up.
Thanks,
DB