Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.
Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.
IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.
Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.
Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.
For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.
So I connect the self test input to the number 2 spot (computer test ground) and use the test light on the number 4 spot (lead to check engine light), sorry I guess I am just making this harder than it really is because I don't understand it.
If your check engine light comes on when you first turn the ignition switch to Run, all you need is a paper clip.
Jumper the self test input dangling wire beside the test connector and the test connector ground. Get in the car and turn the ignition switch to Run and watch the flashes.
OK, finally figured it out, I thought I had to use a test light, all I did was stick a paper clip in the two wires above and got in the car, it flashed twice long pause flashed twice, then flashed 9 fast then 5 fast, but the 95 is fuel puimp power isnt it, my fuel pump works perfectly. What were the other two slow and two slow flashes?
The 95 code is because at one time or another, the fuel pump relay hiccupped and didn't provide power the pump when the computer told it to run. Sometimes this is a one time thing, other times it is a no run or runs poorly condition.