89 LX backfireing intermittenly

[stevesLX]

Not sure what is causing this but I keep getting back fire as I am driving down the road and its loud. What it does is you can take off and the car will run like a bat out of hell but then you can slow down or come to a stop and take off again and it feels like someones holding you back and if you keep your foot in it it will start to backfire. Its back and forth with this. Anny help would be appreciated. I installed new o2 sensors and a new TPS. My timing w/ the spout out is set at 14 degrees I even tried bumping it up to 18 and it still acts the same. Even at 10 degrees it does it. Now I have been having a lot of valvetrain issues with trying to get rid of my valve train noise but I don't think it causing this. My preload on my lifters is at .070 which crane cams said was fine. But like I said I dont think its causing this thing to run fine one minute and likme crap the next and backfiring.

 

[illnotch]

I had the same problem right after installing new O2's. Changed them a month later back to a pair of stock ones, an the back firing and hesitation stopped.

 

[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.

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/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.