Speedometer cable and loping

Check the vacuum line that feeds the MAP sensor. It may have gotten knocked loose.

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 Walmart.

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.

Simon9350 said:

I just bought an 87 GT. Car ran good, changed the oil pressure sending unit, coolant temp sensor, Oil, Air Filter, Speedo cable, Now the car has a terrible lope and runs like crap. Also the speedo cable already quit working how does that thing connect to the speedo gear besides that clip that holds the gear in, Did I do something wrong?

Click to expand...

besides the thin metal clip that holds the speed sensor to the cable, there is a large clip that bolts onto the tranny and holds the speed sensor assembly and cable in place.

in the picture it is the bracket attatched to the speed sensor.

I would say that its ur VSS sensor, or what's it called. that picture above is it. it tells the computer to not drop a certain amount of revs if you have the clutch in while cruising down the road. my was loose after i changed my speedo gear and it had a hanging idle. just make sure its all the way in.