I have a 95 F150 and it gets a rought idle every once in a while. Any Ideas. I was thinking about running some fuel injection cleaner throught it. But I'm wondering if anybody else has seen this it goes so low on idel it feels like it is going to knock off.

Thanks in advance.

Justin

 

You could try some pour-in cleaner, though I doubt that'll fix you problem completely. If you do this, look for K-100 gas additive, it's the only additive I can say from experience actually works(used it for a while in my snowmobiles and jetskis, never been let down). My truck has a similar issue when below 1000 RPM, a kinda "lope" in the idle accompanied by moderate vibration? I ran some K-100 through and there was a noticeable reduction, but it didn't go away. A new air filter(the old one was absolutely filthy) helped bring the RPM's at idle up a little too.

In reality to fix the issue you'll probably have to clean out the throttle body and other intake components, no "mechanic in a bottle" will ever do that completely.

 

Which engine? MAF or MAP? Any modifications or damage? Who does the maintenance, and is it on-schedule? How many miles on the plugs, wires, cap, rotor, fuel filter, & air filter? Any history that might affect the engine? Is the rough idle the ONLY symptom?

 

check all of your vacuum lines to see if any have rotted out or cracked or even came unplugged if you did a recent tune up.

 

5.8 tune up done about 10k ago. and rough or low idle is the only symptom.

 

Ttt

 

Waitin' on you... If you're only gonna answer two at a time, this is gonna take a while.

 

It has the 5.8 Not sure about the MAF or MAP it has the older looking intake with twin tubes going to the air box. Maintenance has been shadetree. Oil and filte done every 3k Cap, rotor, fuel filter and air filter have all been changed in the last 10k. There is know know history of it having problems.

Thanks

 

If it has 2 round hoses at the air filter cover, it's MAP. Try this, then get a Haynes manual & test the ignition system.



If you don't find anything wrong, put a fuel pressure gauge on it, route it out the back of the hood under a wiper, & watch it as you drive, especially when it idles badly.

If the symptom matches what's described in this TSB, a new IAC might help, but you should check everything else first.