95 5.0 Rough Idle

[David Hagerman]

New to Stangnet and I'm looking for some help from my fellow 5.0 owners. I have a 1995 5.0 with 132,xxx miles and automatic transmission. While getting on the highway this morning, I heard a "pop" from under the hood and acceleration was then very rough. It is only rough when accelerating from a dead stop and evens out after approximately 20-25 mph. Upon accelerating after already doing 25 mph or so, it's not rough. I have noticed that it now idles rough too. I checked for vacuum leaks, made sure the plug wires were secure, distributor cap looks fine (no cracks, etc.). These were just a few things I found on the Intranet that may be the cause. The popping sound has me baffled and by the way, only happened the one time. Any suggestions would be appreciated. Thanks!

 

[Mustang5L5]

Was it a lean backfire?

Have you run the codes? OBD-1 cars do not display a check engine all the light when a code is present.

 

[jrichker]

Dump the codes. The how to dump codes is the first thing in the Surging Idle Checklist.

You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the Surging Idle Checklist. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix.

It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 159,000 hits, which indicates it does help fix idle problems quickly and inexpensively.

 

[David Hagerman]

Was it a lean backfire?

Have you run the codes? OBD-1 cars do not display a check engine all the light when a code is present.

Hey Mike. I don't think it was a backfire at all. Reminded me of the sound when popping a cork from a wine bottle. I know that sounds strange. I am going to check the codes. Just assumed that since the CEL isn't on, a code would be present.

 

[David Hagerman]

Dump the codes. The how to dump codes is the first thing in the Surging Idle Checklist.

You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the Surging Idle Checklist. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix.

It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 159,000 hits, which indicates it does help fix idle problems quickly and inexpensively.

Appreciate the info! Looks like I have my weekend cut out for me.

 

[jozsefsz]

In addition to the checklist, check your harmonic balancer. Those will sometimes come apart, potentially making some noise, and then giving you the shakes afterwards.