'04 Ranger with rough idle, and sometimes eats up front brakes

[mhall]

Hi all,

For the last few months (maybe half a year) my 2004 Ranger XLT with the 4.0 L SOHC was running a little bit rough at idle (you could feel it stutter a little, and the tach needle would jump up and down maybe 25 RPMs or so). When I took it in for the 75K service at the local Ford Truck-only dealer last month they said that they thought the throttle was a bit sticky.

I tried to find out from them why they thought it might be doing this but they wouldn't give me a clear explanation of what was happening besides telling me it was sticky and might need a tune-up, and I got really irritated. So then I decided I'd try to take care of it myself instead of trying to get help from people who didn't seem interested in getting to the bottom of the problem.

So I searched quite a while on the net and ended up finding you guys and your incredibly helpful documentation of common issues and discussion threads. So far, I have started by cleaning out the MAF with MAF spray a few days ago which didn't change anything, and yesterday I did that pain-in-the-butt remove the wheel-well job to swap the plugs and wires (thanks again to a discussion thread for revealing the secret to this very tricky job), as well as scrubbing out the IAC with electric spray.

The latest round, swapping the plugs and wires and scrubbing the IAC seemed to help a lot and it is running much, much better, but the idle is still a tiny bit rough. I wondered, how rough is too rough, and how do I decide if the idle is steady enough to be "normal" or if I have more things to check? I was thinking of cleaning the throttle assembly with some intake spray as a possible next move but I wanted to collect some more advice first.

One other question also. Everything has worked great on this car, besides the rough idle, and a seemingly constant need for new front pads and entirely new (NOT machineable) rotors every 1.5 to 2 years, or about 15000 miles, as I don't drive this thing a huge amount of miles. This seems a little weird to me... I don't have to do this nearly as much on most of the other cars I have had in the past. I wondered if it was some kind of design issue affecting all these trucks, such as having rotors that are too small to handle the weight of the truck, or a lack of cooling getting into the wheels and overheating things to cause failure, or if there's something I'm not doing right when I try to follow the factory service guide when I take it to the shop, and I need to change the way I'm getting it serviced.

Thanks,
mhall

 

[gw33gp]

The only thing I can suggest on the rough idle is to check the rubber PCV 90 degree elbow that goes into the intake under the top radiator hose. They have a tendency to degrade and develop a vacuum leak.

I don't have a problem with my front brakes and rotors. Your rotors should be larger than mine because they changed to a larger rotor sometime in 03. I suspect low quality pads and rotors or mismatched in some way. I have always been able to have the rotors turned when replacing the brake pads. I upgraded to Raybestos Super Stop pads on my first brake job at around 40,000 miles. I also installed the higher quality Raybestos rotors. Now, I have two sets of rotors (the original and the Raybestos) and can get the spare set turned before I do a brake job. When they stopped making the Super Stop pads I switched to Akebono pads and I have been satisfied with them so far. I get 50K to 60K miles out of the upgraded pads.

I did notice I was getting somewhat high wear on the front pads (a lot of brake dust) when I first switched to the Raybestos pads. They were working so much better than the original pads that they were doing most of the braking because the rear shoes were still the originals. I then installed Super Stop shoes on the rear and all was well. Maybe you need to put better shoes on the rear or make sure they are adjusted right.

 

[adsm08]

Check the adjustment of your rear brakes.

Also, I would find out why the rotors are always not machinable. Are they wearing too thin that fast (ceramic pads will do this to them) or are they rusting up? Rust and pits make for a surface that cannot be properly machined. Also, what kind of rotors are you buying? Cheap rotors will wear out quicker than high quality ones.

 

[mhall]

Thanks for the advice, guys.

I will be sure to ask what's wrong with the rotors in the future, I am due for a free set of tires-for-life from my original dealer who does a better job than the local ones where I live now, and I can ask them about the rotors when I go in, and inspect them myself and get a picture for you guys too.

I didn't know enough to ask for details about their condition until I started reading up after the latest issues and getting advice from all of your threads about the different ways the rotors could fail on me.

The part I'm confused on is that I always went to actual Ford dealers so I was assuming I would be getting Motorcraft original quality brake parts... but you guys are talking about using other brands besides that. So I'm wondering if maybe the Motorcraft brake parts aren't that great and I should switch to a different brand and do the work myself this time, or do you think maybe the dealers could have cut corners and given me some inferior rotors and pads, or goofed up the adjustments on them?

Meanwhile I'll be sure to check the PCV hoses carefully when I swap the valve out this week... I do hear a very quiet hissing sound when the truck is idling, I thought it was a normal part of the engine's sound because it's done this quite a long time, but maybe it's actually a bit of a vacuum leak instead. We shall see.

 

[Dune Runner]

The vacuum leak is very common on those engines. Google it and get ready to read. Might check and see if your calipers are hanging up and dragging too. I agree with adjusting your rears though. I adjusted mine a few weeks ago and they needed it bad.

 

[Mcleary316]

Like the others said, check for a vacuum leak. Also try running some Seafoam through the system. Helped with my trucks idle a bit. Used to bounce around a tiny amount and now its smooth as butter!

 

[robertc1024]

The vacuum leak is very common on those engines. Google it and get ready to read. Might check and see if your calipers are hanging up and dragging too. I agree with adjusting your rears though. I adjusted mine a few weeks ago and they needed it bad.

+1 on this. Ranger calipers sticking is somewhat common. Mine did it bad enough that it made the truck un-driveable.