Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: TheCowboyKiller on March 08, 2017, 06:58:47 PM

Title: Rough Idle on 88' 3.8L
Post by: TheCowboyKiller on March 08, 2017, 06:58:47 PM
I started driving my Cougar as my daily driver a few weeks ago. As expected the car is started to reveal some issues that probably developed from it sitting for a long time. I've already replaced the radiator, U joints, thermostat, fuel sender and seat belts. I thought I was in the clear and started driving it long distances. Yesterday on the way home I pulled off the highway and as I sat at the intersection I noticed a rough idle that wasn't there before. It is a consistent "wobbling" back and forth type of idle and the engine only feels off when the car is stopped and idling. I checked vacuum lines today and found the tube coming off the intake plenum had worn a little from rubbing on a bracket but it hadn't worn through. I taped it up anyway but that made no difference. Everything else looked normal. Throttle body was clean, and no other strange noises. Any ideas on what else to check?
Title: Rough Idle on 88' 3.8L
Post by: Haystack on March 08, 2017, 09:38:31 PM
Run codes. If nothing comes up, double check all the vacuum lines and try a base idle reset.

Prretty much only the iac and tps really effect idle, but certain other codes can change how the computer compensates at idle, so do that first.
Title: Rough Idle on 88' 3.8L
Post by: TheCowboyKiller on March 09, 2017, 12:58:58 PM
Do you mind giving me a brief run down on how to check the car's codes?
I'd certainly appreciate it!
Title: Rough Idle on 88' 3.8L
Post by: Haystack on March 09, 2017, 01:36:25 PM
https://www.youtube.com/watch?v=z0ehA8cFTkc key one engine off self test.
https://www.youtube.com/watch?v=9QSiS6wf7oU key on engine running self test.
video of me running codes on my 87 tbird, I show you what to look for, how it works and what to hook up. sorry for the cruddy video.

http://sbftech.com/index.php?/topic,849.0.html
a quick web page to browse so that you can see what you need and what the codes mean.

base idle reset instructions.
http://sbftech.com/index.php/topic,1031.0.html

if ya get stuck or need any help, let us know and we should be able to help you. Since you have a 88 3.8 all the procedures should be pretty much the same as all the instructions for a 5.0. One thing I do when I run codes, I take a video of the flashes so I can refer back to them later.
Title: Rough Idle on 88' 3.8L
Post by: TheCowboyKiller on March 09, 2017, 03:04:44 PM
Thanks man! Ill try it out tonight if I have time or tomorrow and post the results
Title: Rough Idle on 88' 3.8L
Post by: TheCowboyKiller on March 25, 2017, 02:53:17 PM
Would a code 41 indicate I have a bad O2 sensor?

This is what the code reads:

41 - System Indicates Lean -passenger side(R), No o2 Sensor Switching Detected. always lean -passenger side(M)