popping and backfiring out of exhaust

I had a similar situation and it turned out to be a rotten/broken vacuum hose on the underside of my upper intake. You may have to pull the upper to get to it. Poke around some and see if you see hear or feel anything.

Dave

popping on decel is pretty normal

OL' WHITEY said:

I had a similar situation and it turned out to be a rotten/broken vacuum hose on the underside of my upper intake. You may have to pull the upper to get to it. Poke around some and see if you see hear or feel anything.

Dave

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found this same problem when i went to do my valvesprings. the oil ruins the hoses or in my case the cap. i had a weird hissing sound for a lil while and the car jus didnt run good anymore. no popping though. jus running really rich.

Do the basics first...

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 Wal-Mart.

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.

Wal-Mart may now have the LCD display scanner for less than $35

my popping was solved with a spark plug change

i had the same problem and it changed when i changed the dizzy

I have the same thing going on, bugs the heck outta me. I'm gonna check my vacuum lines again. Plugs didn't solve mine, I'd run regular, side gapped, and regular + MSD and no change...