Strange Random Misfire

[94svtcobra302]

okay so i have a 94 cobra that has about 7k miles on it since the motor has been rebuilt, it has a new ignition system ; which consists of a new coil, plugs, spark plugs, rebuilt distributor, and ignition coil; and just put a new fuel filter on it. When the car is cold it has a misfire that is present throught the rpm range when your barely giving it any gas. But as if you give it more gas the misfire goes away. The problem gets better as the car warms up, and eventually goes away when its at full operating temp and your just idling along. But if you try to get on it the car wont rev past 3k, if you try to go past that it stumbles and misfires and just has no power

 

[90lxwhite]

Codes?

 

[toyman]

Ever cleaned the MAF sensor?

 

[94svtcobra302]

theres no check engine light and the maf was cleaned when the engine was rebuilt

 

[Mustang5L5]

theres no check engine light and the maf was cleaned when the engine was rebuilt

Only 13 of the possible 99 codes actually trip the check engine light on an EEC-IV car. So it's possible to have tons of codes, and never see the CEL.

Also, at the end of the code reading process is a test called the "cylinder balance test". What it does is turns off the injectors one at a time to identify a misfire and tell you which cylinder it is on. REALLY helpful diagnostic tool.

So for your car, first thing i'd do is run the codes, and perform the cylinder balance test.

A search will find plenty of posts on how to do this. For a code reader, i'd really recommend this one. You can also jumper the test plug and count blinks as well.

http://www.amazon.com/dp/B000EW0KHW/?tag=stangnet-20

How to perform the code test and cylinder balance test without the reader (post #2)

http://www.stangnet.com/mustang-forums/threads/checking-engine-codes.868753/

Info on performing the "cylinder balance test"
http://www.stangnet.com/mustang-forums/threads/cylinder-balance-test.695039/