Unusal Problem

[jobar]

Hey fellas. I need some help here. I was driving to work this morning and my truck started acting funny. My idle was up around 13-1400 rpm. When I would go to shift, I would push the clutch in and the front end would drop. Felt like the truck was loaded up and once I pushed the clutch in, it would release the load. That's the best way I know how to describe it. It also sounded funny coming out of the exhaust. Like its skipping a beat. I changed out the water pump, alternator, tenisor, tenisor pulley, idler pulley and serpentine belt last week. Truck drove fine all week. I filled the truck up this morning, then it started acting funny. I would suspect bad gas but that gas station has never given me any problems before and I am not so sure bad gas would make the truck load up like that.

Wasn't sure where to post this. Mods feel free to move. Thanks for any help fellas. 2001 Edge, 3.0, 5 speed.

 

[RonD]

Is it a Flex fuel system?

Depending on outside temp 1300 cold idle is only a bit high, but since you mention it I assume it is not normal for your engine to run that way.
Bad gas(too much water) would give you stumbling and backfires at times.
Did all the hoses get hooked back up, a small air leak can cause the higher idle.
I would double check, sometimes things can get pulled off when moving other things around, lol, excuse the technical jargon.

Check PCV hose especially at the elbows, these have a tendency to fail when they get over 10 years old, it has become a common Ford issue.

Check to make sure brakes are not dragging, that can produce the symptom of "extra load" you describe.

Also double check serpentine belt routing, I have reversed a pulley or two in my day

 

[Mark_88]

It sounds to me like front brakes locked up too...like when you put the clutch in, the engine is no longer pushing and the front drops because the front brakes are grabbing...

 

[jobar]

RonD-It is not a flex fuel system and 1300 rpm is hot idle. I tried to check all the hoses during my lunch break, everything seems to be hooked back up the right way. I checked the PVC hose and it looks like it has never been touched. Could be the original one. No telling unless I pull it out. Now to the brakes for you and Mark_88. I rebuilt the rear brakes this past year so I know everything in the back is fairly new, however the front brakes do need new pads. I put the truck in neutral and it seemed to roll really easy. I rolled it back and forth while standing at all 4 corners and didnt notice and resistance. The only way to know for sure is to get it home tonight and pull all my tires off. Also need to go trough my truck and replace some hoses. Some are questionable. Might explain high idle.

 

[jobar]

Just out of curiosity, would a fuel filter cause any of my problems described?

 

[Mark_88]

The fuel filter probably wouldn't cause it because, if anything, you'd notice severe stumbling due to lack of fuel...high idle can be caused by a few things, including a vacuum line being off as RonD mentioned...

When I had a similar problem it was caused by the flex lines were worn (more like collapsing) and at first the brakes would grab sporadically so driving became a bit of a challenge due to the engine fighting the front brakes...but I did not experience high idle...

Could be a combination of things all springing up at once...does happen...

 

[RonD]

Does it idle higher when cold and then drop to 1300rpms?

If not then IAC valve could be unhooked, you should get a CEL(check engine light) with that through.
Or IAC valve may not be responding to computer control, again that should get a CEL.

Idle changing RPMs when cold and warm means IAC is working.

You can shut off engine, unhook IAC valve and restart engine, you should get a CEL and idle may be up and down if there is a vacuum leak, without computer control there can be no correction for idle speed.

As for the brakes, could also be power assist is sticking on a bit when used, inside the cab is the "atmosphere valve" for the booster, when you press down on the brake pedal this valve opens and outside air pressure goes in to booster and presses against the lower pressure(vacuum) side of the diaphragm, this adds to your foot pressure on the pedal, so it is the "power" in the power brakes.
If the "atmosphere valve" isn't closing all the way when foot is off the brake then a slight pressure would remain on master cylinder as long as there is "vacuum" in one side of the booster.