Hesitation problem, need help

[Wicked 97TA]

I'm new here and not a Mustang guy as you can probably tell by my screen name. But my dad is a Mustang guy and has a '93 5.0 LX hatchback he just bought not too long ago. The problem with it is that at about half throttle it feels like it is making good power. If you go from there and lay all the way into it it just lays down and feel like it won't make anymore power. He has changed the fuel pump and tried to tune on it a bit. Somebody told him that he could be getting a vacuum leak from somewhere in the '98 Explorer upper and lower intake manifold that the previous ower had put on it. We have since then put back on a stock upper and lower intake.

Does anyone on here have any idea what could be going on with it?

 

[nito88stang]

Check the TPS sensor on the throttle body. Make sure that at WOT it is reading in the 4v-5v range. Also check fuel filter and clean the MAF sensor.

 

[HISSIN50]

welcome to the boards.

i would pull codes first.

how is the FP at near WOT (when it runs limp)? if the regulator is bad, that could be bleeding off pressure (if one suspects a fuel issue). MAF wire clean?
TPS check out alright?

good luck.

 

[TorontoJohn]

could do the ol' quick start spray vacum leak inspection. Just spray some quick stary near vacum lines and if the rev's go up you know there is a leak there.

 

[jrichker]

Dump the codes and see what the computer says is wrong…

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.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/article...c-iv_codes.html

IF your car is an 88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 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 Walmart .

No codes, do the plugs, wires, cap, rotor, fuel filter,& air filter tune up.