Weird miss at higher rpms, need help

noslow1986 said:

hey join the club i have the same problem. been 2 weeks i still cant figure it out

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I have also encountered these problems with my 90 stang, except it sounds like its having an intake backire (or just detonation). I have changed the fuel filter, spark plugs, cap and rotor, wires, coil, vaccum check, fuel pressure check(42 PSI), timing set at 10 degrees. The only thing I could think of is that the voltage on my TPS is off. I pulled some codes also and I think 95 came up the most and believed it was fuel injectors, fuel pressure, fuel lines, and oxygen sensors.

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.



See http://www.troublecodes.net/Ford/
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

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.

Or for a nicer scanner see http://www.midwayautosupply.com/detailedproductdescription.asp?3829 – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $35.

Wal-Mart may now have the LCD display scanner for less than $35

Reduce the plug gap to .024" to see if the miss goes away. If it does your ignition system needs help.

on my 347 i use a crane hi-6 with a ps92 coil, motorsport 9mm wires, autolite 3925 plugs gaped at .080, pulls fine to my 6,500 rev limit