hi,i just purchased a 77 280z in good condition.i did the basic tune up and im happy with the car but it is relativly slow and seems too be working to hard at high rpms with little acceleration any advice would be appreciated thanks.

 

First try running fuel injection cleaner in your next two tanks of gas.

 

if you havent changed your plugs and wires make sure to do so.. also air and fuel filters. fuel injector cleaner is also an easy first step that might fix things. think of the engine as an air pump, powered by the explosions in the combustion chamber.. if the air pickup, the air filter, is not clear it won't pump too well. you might also want to clean the inside of the throttle body.. this is a fairly straightforward procedure, and involves removing the air flow meter, and probably the filterbox as well from in front of the throttle body, holding the throttle open with your finger, and spraying carb cleaner in there and scrubbing as much out with a rag/toothbrush/whatever implement of destruction you could use to clean it out... air from the engine crankcase flows through there in order to maintain vacuum, so over the years alot of gunk can build up in there from the engine oil etc etc.. Another possibility is that there is something wrong with your catalytic converter. I had a friend with a 92 camaro once, and we were driving down the road and suddenly something happened, and his motor was running like half the cylinders had stopped firing.. what happened was the ceramic inside the catalytic converter had broken, and a chunk was laying broadside against the honeycomb through which all the exhaust gas flows. this was blocking the air being pumped out of the engine.. the exhaust. i dont know what emission laws are like where you live, but if this were my car id take the catalytic converter off, and stick a big screwdriver through it a few times :- ) this has the effect of totally removing the ceramic honeycomb, and msking your cat a non-functional, free-flowing chamber. this is not the best idea under all circumstances though.. especially not from the point of view of some local law and smog authorities, so be careful with that one. a surer, and probably better (but more expensive) way to go would be to pick up an aftermarket exhaust system. you can get them to bolt directly onto your stock exhaust manifold and replace everything from the engine pipes back, or you could get a cat-back system (bolts onto the back of the catalytic converter.) You could also get a complete system, headers and all, but thats a bit longer-term... I 've driven a 75 280 for four years, and at times (especially after driving through heavy rain and flooding, and after doing seemingly unrelated days-long jobs on the car like a clutch) ive found that i start it up and it idles rough, and has no power, but runs consistently, VERY weakly, and loud and rough. when this happens, i usually get some wd-40 and compressed air, and disconnect the plugs on all the FI stuff one at a time, and clean them out real good. i know for a fact that my throttle position sensor plug alone has caused my car to run weird several times and it took me forever to come across that as a treatment.

well, thats kind of a long post.. but there are alot of things that can rob an engine of power... if you think of it as an air pump, it helps to brainstorm other possible things that can be wrong, and then figure out and fix your problem.. once you play with the fuel injection for a year or two you start to get a knack for figuring out what is causing problems.

 

Lots of people remove or modify their cat converters. Just so you guys know, it is a Federal offense to knowingly remove or modify it and carries a $15,000 fine! If you live where you car has to be smog compliant you might consider a high flow cat from Summit Racing for $55.

 

Thanks for the advice,i have yet to pick up plug cables got new plugs though and am currantly running MarvelMysteryOil in the gas tank. As for the tune up i changed the sparkplugs,oil,and oil filter.This is my first car and i want to do it justice.

 

beyond your standard oil change every 3000 miles, its good to change the air filter about once every year or two (depending on how much you drive and how dirty the air you drive through gets.) you also might try a distributor cap and rotor, they need to be changed regularly too and thats always a good thing to do on a new old car.

 

I have a 75 that went through the same problem . The fix for me was the gas tank , it had some rust and crud in it , the car ideled fine but under load would just choke, pulled the tank and cleaned and sealed it then replaced my filters and ran some injector cleaner through it and all is good now the clue was i started to hear the fual pump whine a bit . Im a chef by trade so this wrenching stuff is kind of wierd for me , but the early Zs have always been a dream car for me but to afford one I am haveing to learn to do the work myself a whole new world of grease.