I got my Vette just a couple months ago and I can't get it right. When I got it she had a little miss, and the fans weren't working. I threw in a new sending unit between third and fourth cylinder passenger side and the temp sensor at the water pump. Now I had only babied her so far for fear of overheating but now confident in running cool, I drove normally. As I got to 2k she feel flat not revving any higher nothing just sounded like a stutter box. I eased of and hit her again, launched like Apollo and gone. This was the case for a day or so. New plugs wires cap rotor and carb clean two cans and no change. New coil, no change. Shows check engine unless you get on it. WOT and the light is gone. As you drive highway speeds she runs smooth when the light is on all of a sudden she misses, spits through the Throttle bodies, and the light goes out. Bought the OBD reader from Autozone code 12 nothing else. Fuel filter no change. PCV no change. Best milage according to avg gauge is 10 mpg. Now she is getting worse and the mpg gauge while set on average is all over the place, every portion of a second from 28 to 0. What gives? Any and all help is appreciated. Even the Chevy dealer says I got a guy been working here a long time he might know something... I am in south central PA and can't find anyone who hasn't said four barrel. I don't want to!

 

If you get a check engine light there has to be a code in there somewhere. Did you follow the directions in the FSM to read your codes?

You mention it fell flat.. what your fuel pressure at both idle and while driving?
should be between 9-13.
Don't worry about the 4 barrell comment... people that don't know the CFI tend to prejudge and blurt out BS...

 

I agree, start with a fuel pressure guage under the rail, and see how it acts from start up , through all types of driving....... then report back.

 

I should get the chance this weekend. I have been looking thru previous posts and thought it strange to attach a gauge to the windshield but here goes. I will let you know.

 

Its the best way bud...

 

i missed the first half of qws question. I not only showed no codes on my tester, but a friend has a shop and his only code was MAP, which we replaced, no difference. actually it smoothed to purr with the MAP plugged, until you touched the pedal.

 

Unfortunetly the 84 has no fuel rail nor schrader valve. You'll have to take the fuel line between the tb's out and go have a tee installed into it. The side arm of that tee you'll want a 1/4 npt so you can screw your connectors in for the fuel gauge. Once you have this there it will always be there for future needs.

Map code.... off memory that would be a code 33 I think.
Check your plug connector at the MAP sensor. And just for the heck of it grab a vac gauge...unplug the vac line to the map and see what you get.

 

I learned something new....

 

You can hook into the main fuel line at the fuel filter. This is just fine to check the pressure. The front throttle body is not going to add any fuel pressure so it not necessary to go between the tbi units for a quick FP test, though its nice to have one for future testing.