Recently I checked the gas mileage that I am getting now with my 1990 300ZX. It appears as though I am only averaging 16.3 mpg. The vehicle has 163,000 miles on it and has been tuned up within the last 8 months. Just out of curiosity, what kind of mileage are you guys getting with your Z-32s(1990-1996 non-turbos)? When mine was new, it would average around 24 mpg.
V.H.
I get 24 - 26 highway with a 1993 300Z 2+2. I would check the air filters or see if the CAT's are clogged.
Have someone check the ignition timing. I've seen a few of the early cars have problems with the drive peg wearing in the drivers side exhaust cam which retards the timing slowly over time. That or maybe you have some weak O2 sensors making it run rich?
V.H. ( snipped-for-privacy@thecomputer.com) wrote on Wednesday 26 May 2004 10:06 am:
If I go 55-60 MPH on the freeway, I get about 30 MPG on my '90 twin turbo. I've never gotten anything as low as 16, AFAIk.
before my tranny locked up (see my recent post :) I would get about 14-20 MPG average, if I PUSHED her hard, less if PUSHED EVEN Harder ;-) but a fair 18-24 MPG City/Hwy if I drove her gently. 55-65 MPH and NO hard accelerations
That's what I'd be trying. Put a couple of new O2 sensors and replace the FI temp sensor and it's connector. If it's a NA, junka odd to have valve problems, if it was a turbo I have seen a couple of them with roasted valves. I have seen them with high miles have low compression when they are running too rich due to washed down cyl walls. Most "pulled out" of it once the rich condition was corrected.
Steve,
The car is DEFINITELY running rich. Wouldn't pass the low speed idle emissions test this year in N.C. Local mechanic says it needs a valve job--and that cylinder no. 5 is skipping. He performed a cylinder leakdown test on the car for me. However, this problem could be coupled with some weak 02 sensors. Other than this problem, the car cranks and runs fine. I still enjoy driving it after all these years. May just hang on to it for several more years to come.
V.H.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.