Loss of Power? Can't figure this out.

[ErikZ]

I have and 88 5.0 GT, manual.

As I reach around 2000 rpms I lose a lot of power and my car feels like it is choking REAL bad. Now, sometimes it runs fine, but it happens almost everytime i drive. I have found a quick temporary fix. As I am driving down the road, i'll turn my car off for a few seconds, then turn it back on and give it a couple good revs. Most of the time it "resets" whatever is wrong, i guess. But, it always comes back.

It almost feels like i'm not getting fuel or something. Someone was also telling me I may have a vacumm problem, or it may be a fuel pump, or a distributor.

I am tired of throwing parts at it now and getting different answers from different people, none of whom have owned a mustang.

The car has about 140k on it. I have already replaced the plugs, wires, cap, and rotor. As well as the TPS sensor, ignition control module, ignition coil, and the fuel filter. Although all that stuff is making it run a lot stronger, nothing fixed my issue.

Has anyone else had this problem?

 

[jhonda]

I am having the same kinda problem...couldn't get a answer on here. I found if I slam on brakes when coming to a stop sometimes my power comes back

 

[jrichker]

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 Troublcodes.net Trouble Codes OBD & OBD2 Trouble Codes and Technical info & Tool Store. By BAT Auto Technical

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.

The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.

The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.


There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.

What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems.

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.

Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® 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 EQUUS DIGITAL FORD CODE READER (3145) – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.

 

[Strype]

A couple of things to keep in mind from personal experience...

a) Vacuum leak. Spray carb cleaner while car is running to find a leak.

b) Loose wire to the ignition switch

c) Distributor or control module