I have a 90 LX with a factory 5.0 in it. I have New Cast heads with angle job, Newer GT-40 Intake, 70mm Throttle body and EGR. 76mm Mass air set for 24lb injectors, have 24lb injectors, Manual Fuel pressure regulator, 190lph Ford Racing Fuel pump, New Fuel filter, MSD 6al, 8.5mm wires, new plugs, MSD e-coil, 1.6 ford raceing rocker arms. Bottom end is still stock. My problem is that it starts fine and runs fine. But when at idle around 800, 900 rpms if I step on the gas to reb it up, the rpms drop down to like 500 and it sounds like it is going to die for like a second or two, then it rebs up just fine. But if I have it running at like 1500 or so and step on the gas it doesn't stutter one bit. I think it might be my timing, It is still set at factory setting. And Ideas would help.
Poor throttle Response
- Thread starter n8sfxdx05
- Start date
I would definately advance your timing to atleast 12 degrees, adjust the fuel pressure to around 38 to 40 psi and check your throttle position sensor. Set it to around .97 to 1.0 and see what you have then. May be something else but that would get you started atleast.
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. You watch the flashing test lamp or Check Engine Light and count the flashes.
See http://www.troublecodes.net/Ford/
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.
89 through 95 cars have a working Check Engine light. Watch it instead of a test lamp.
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/pc-7208-90-equus-digital-ford-code-reader-3145.aspx – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.
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. You watch the flashing test lamp or Check Engine Light and count the flashes.
See http://www.troublecodes.net/Ford/
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.
89 through 95 cars have a working Check Engine light. Watch it instead of a test lamp.
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/pc-7208-90-equus-digital-ford-code-reader-3145.aspx – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.
mustangfan1990
New Member
no thats not too high. I would say sounds like something with your MAF sensor if it is bad or unplugged the motor will hesitate when you try to rev it up
I highly recommend that you go back and re-read my previous post. A bad MAF will set code 66.
IF you read my "Dump the codes" post, you will find how the dump the codes with a paper clip. No code reader is needed.
Post any codes you get and I will post the 5.0 Mustang specific code definitions along with the fix for the problems. Properly done mods don't set codes.
