Help!!! Car Bogs under load

Dumping the computer diagnostic codes on 86-95 Mustangs

Revised 19-May-2009 to update drawing for dumping the codes on 86-88 Mustangs with no check engine light.

Here's the way 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.

Be sure to turn off the A/C, and put the transmission in neutral when dumping the codes. Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.

Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.

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.


WARNING!!! 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.
Or for a nicer scanner see http://www.midwayautosupply.com/p-7208-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.

You should see an 11 code since that says the computer passed internal diagnostics. No 11 code, and there are problems in the computer or wiring.

bgraiders323 said:

Well I scanned it with a scanner. It just says "system pass"

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That's not much help for you. If you got no codes and have major driveability problems, something is definitely off key.

Did you dump the engine running codes (KOER) as well as the engine not running codes (KOEO)?

Does the cold air kit pick up air from inside the engine compartment or from under the fender?

If from under the fender, have you tried rotating the MAF housing to see if changing the airflow through the MAF changes the performance?

If from the engine compartment, that is the likely source of your problem. The heat and turbulence from the engine compartment air will upset the airflow through the MAF, upsetting performance.

I would pinch down on that gap a little .0044 or so. also would inspect the spark plug wires really well make sure none of them are damaged and grounding out on anything. Does it only bog under load or while free reved?

Its worth a shot, seems like it could be spark blow out. I've had this happen before with my lightning. If that don't help I would test out the coil. Could be weak.

bgraiders323 said:

Yea I checked koeo and koer. And no faulty codes

It goes into the fender. Yea I read about clocking it a different position but does it matter. What position I clock it? 3 o' clock or 9 o' clock or 6 o' clock????

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Rotate the MAF housing in 45 degree increments until you observe a positive change in performance.

Ignition problems:
Spark plug wire is actually misinformation, because there is no actual wire in 99% of the so called spark plug wires. Instead, most are fiberglass or Kevlar strands with a carbon coating on them. The problem is that the coating is subject to breakage at the terminal ends and when the “wire” is bent excessively or subject to abuse such as jerking the boots off the spark plugs. Some Taylor, Magnacore & Accel wires are a spiral wound steel wire and make claims for increased performance. All of these wires have reduced EMI (electromagnetic interference) to prevent problems with electronic fuel injection, radio and other electronic system in the car.

The typical spark plug “wire” will have about 3000-4000 ohms per foot resistance. A 2 ft wire would be 6000-8000 ohms, and a 3 ft wire would be 9000-12000 ohms. More than this is suspect and may cause problems. Spiral wound metal core wire may run from 1-20 ohms per foot. Due to the fact that the spark is a pulse, the actual energy at the spark plug tip may not be substantially greater than the other types of spark plug conductors.

See http://www.magnecor.com/magnecor1/truth.htm for more information.

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