i have a 1996 f-150 with the I-6 5 spd and the engine always idles kind of rough after the engine has warmed up. What are EFFECTIVE things that i can do to solve this problem?

 

full tune up, change the fuel filter. is it throwing any codes?




Jim

 

Sounds like an EGR stuck open problem

 

i already changed the fuel filter and got some of that injector cleaner stuff. other than that, the next thing im gonna try and do is get like 5 quarts of the unconcintrated injector cleaner and put about 5 gallons in the rear tank to clean the crap out of the injectors. if that doesnt work, ill get a full tune up.

 

definitely check your EGR




Jim

 

what is this EGR?

 

Could be Idle Air Control valve or Throttle Position Sensor. By rough idle what exactly do you mean? Surging? Usually EGR will not cause surging, it will just choke and struggle to stay alive, and usually more so under throttle than at idle. Run injector cleaner in fuel (Seafoam works well), Seafoam through throttle body, DO A TUNE-UP!! (plugs, wires, dist cap & rotor), check/replace IAC, check/replace TPS.

EGR = Exhaust Gas Recirculation. The EGR valve opens and closes to allow exhaust gases back into the combustion chamber. It usually opens at no/low throttle and closes at WOT. Usually when malfunctioning the EGR valve will either stick open or stick shut. Stuck shut doesnt seem to present a problem with the engine operation as it is just getting 100% fresh air (like it would at WOT). Stuck open would be an issue though as it would be allowing too much exhaust gas (not enough 02) into the combustion chamber, resulting in poor operation. But a bad EGR valve would typically not cause problems/surging at idle (the valve would have to be flopping open and closed to do this.. but if it is able to flap open and closed then it is NOT MALFUNCTIONING!! lol). I would perform the above checks/maintanence before replacing the EGR valve(~$75). Most of them are things that need to be done anyway.

-Chris

-Chris

 

What he said^^^^ Was thinking about the IAC when I typed, just typed in EGR for some stupid reason


Jim

 

yea, its not like surging, its more like it will kind of kick a little once about every 2 or 3 seconds. ill run more injector cleaner then ill clean the throttle body. if that doesnt work, ill get a new EGR valve i guess. thanks.

 

Oh! Forgot to mention. Before anything else, CHECK THE CODES!! It's free, and often times can give you huge hints (or exact solutions) to your problem. Even if you have never seen the check engine light come on, you could still be getting codes from some of the sensors.

-Chris

 

You're not listening man. I don't think its the EGR. EGR is typically not going to cause IDLING issues as it could be open or closed at idle without any problem. You want to check codes, do a tuneup, clean TB, and check IAC & TPS. If you want to replace the EGR valve go for it, I don't think it is going to fix your problem...

-Chris

 

that little bit every 2 or 3 seconds points to the IAC but get your codes checked first




Jim

 

ill do that, thanks.

 

Agreed, IAC is the most obvious culprit but it's good maintenance to clean the TB and do a tuneup. If you're on a budget or in a hurry then skip to the IAC first and then proceed to the other things...

-Chris

 

Although it may not be the cause of his particular problem, a stuck open or unable to close all the way EGR will DEFINATELY cause a very rough idle. The EGR is supposed to be fully closed at idle, and opened at it's max during normal cruise, then tapering off slightly during high acceleration low vacuum situations.

It's also the easiest to check. Simply remove it where it bolts to the intake manifold, and install a makeshift gasket with no hole in it to block any exaust that may be getting through it. And it doesn't cost anything.