Running Rough, No power

[mclelm]

I hope I'm entering this message on a general forum in your website. I'm hoping one of your readers can help me. I've got a '92 Mustang with a 2.3L and an AT. It was running very badly last spring. A major tune-up including replacing the wires just to be able to put it on the computer was done. The ignition module was replaced; it fixed the problem for a week. It was thought by the mechanic who has worked on it for the past 10 yrs, that the ignition module was defective so it was replaced. Again the problem was fixed for a short time. When I mentioned that the car runs better when the tach is working, he took the tach apart but couldn't find anything wrong with it. The car was taken to an automotive electrical repair/rebuilding garage in the city. They couldn't figure out what was wrong with it. After spending about $900 on the car it still ran poorly. But then much better once the engine warms up. Now the car uses excessive fuel; you can smell it when the car first starts. It feels like it's running on 2 cylinders. It's very rough without much power. I have to floor it to get any speed. It can get up to 60 km/hr in a long block. It runs very rough sitting at red lights. When the car warms up (to the second tick on the temp gauge) the car will suddenly run beautifully with lots of power (well lots for a 2.3L). But sometimes when I take my foot of the gas, the car will run rough again. I had to drive it on a very cold day without plugging it in; it started perfectly and ran well for a short time. Last week I had it in at a garage for some exhaust work. The car was inside for about a half hour. It ran perfectly for half the ride home and then was rough when I took my foot off the gas at a red light. My mechanic says it is probably one of the 5 sensors. I don't want to spend another fortune on repairs. Have any of your members had a similar problem, or know which sensor it could be? I would appreciate any information. Thank-you, mclelm

[84LX89GT]

I had a '91 2.3L mustang that did what you're talking about, what happened was one of the ignition coil packs would intermittently fail and run rough and then run good again. After 1 ignition coil and module replacement it ran good for almost a year before it did it again.... I replaced the other coil and it ran fine....until i wrecked it.

Note: just like you described the engine would run on only 2 cylinders. Each coil pack is in charge of 2 cylinders. It is a waste spark system meaning that the other plugs/wires fire on the exhaust stroke, each pack has 2 ignition wires and 2 waste spark wires going to them.

Chances are that you have a coil going out.

[91mustangowner]

i'll agree with 84LX. it is deffinatly your coil packs......i have a 91 2.3 with the duel fire system so i got two coil packs so i got 8 sparks plugs.... 2 plugs per cylinder one other thing you might try replacing.....and you can do this yourself.......is the O2 sensor....even after i replaced the coil packs it still gave me little sputtering and shaking fits until i got a new oxygen sensor....been running good ever since