I bought my current 94 Z with a busted Opti.After replacing it, the first thing I noticed was it was real slow compared to my last four Z's,and im only averaging about 170 a tank,about 11 mpg.So far no codes but i have replaced coil,wires,plugs,opti,water pump,cleaned out throttle body,new coolant temp sensor,ect.It idles smooth as butter, shifts just fine,just no power,and the o2s look fairly new.I cant get any info out of the last owner cause he only had it a week then Opti went out.What should i be looking for?

 

What is the RPM reading at 55mph???? Might have lower gears?? Auto or manual?? How many miles on engine??

 

2:73 gears ,read it off the glove box,auto,140000 miles,rpm at 65 is a lil over 2000.

 

Time for a tune up. Perform a leakdown test. Use datamasters or something and see if the O2 sensors are doing their job.

 

Everything is a month old, I have replqaced everything but the o2s, and they were put on soon befor i bought the car.But that doesnt mean anything.

 

You need to get a good scan tool on it. See if anything looks awry.

 

Compression test- see if you are getting the energy out of the fuel you are burning-

Brakes dragging? Soft tires? You are wasting energy somewhere, pushing that down the road.

 

Runs, drives fine, brakes, tires ok.I just need to find someone around here who can datalog.

 

Check the accuracy of your tach with a scan tool. It's not uncommon for them to be way off on our cars. 65mph in 4th on a 4L60E with 2.73 rear gears should give you 1500 rpm.

If you find that the tach is accurate, this might be a clue about the problem (slipping trans?).

 

I"ll check that!If I punch it from a dead stop,it shifts just fine in all gears,and ill check the rpm again .I was just going by what i thought i rememberedI was thinking also that someone told me if the gromet on the map sensor is rotted, it might give it a false reading and ritchen it up.

 

Not really, the fuel trims (o2 sensors) should compensate.

 

ok cool.Im looking for someone who can datalog aroud here.Theres a few shops that mainly do ls1, but have lt1 logging stuff too.That should tell me exactly what my cars doing.

 

Where is "here"?

 

Springfield Mo.Theres a few race shops around here.

 

I have talked to you over pm before right? I have a laptop with datamaster and freescan on it for odb1 stuff. PM me if you want to meet up.