Engine Bucking-- IAC??

stang9215

New Member
Sep 20, 2007
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Northeast
I have a quick question about the IAC -- can a faulty IAC cause the car to buck when under partial throttle? My car bucks when cruising down the road (usually between 1600 -- 2100 rpms). The bucking goes away once I back off then reapply under a heavier throttle. Can this be attributed to a bad IAC? Any help would be appreciated
 
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/

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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.

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

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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.
 
A vacuum leak is another possibility, though all my vacuum lines were checked. My O2 sensors are pretty old (haven't been replaced since 1997), so replacing them may be a simple fix. The car is not a daily driver, but the O2 sensors probably have 30-40k miles on them.