Speedo doing a full sweep says power supply issues, make sure your battery terminals and grounds are good and tight. Be warned the terminals will seem tight but aren't if you can grab then and twist by hand. Lousy terminal design. Cleaning them one time can make them slip, especially the plus side.

 

I'll check it out today. Thanks! do you have any idea what's causing the stumbling during acceleration?

mine was the alternator ,and very easy to change,and a good clean up of battery terminals,and ground points,PCV was not a problem and has been good for 201 k miles.

That was a fix to the speedometer problems I assume?

 

mine was the alternator ,and very easy to change,and a good clean up of battery terminals,and ground points,PCV was not a problem and has been good for 201 k miles.

 

UPDATE:

Today, I checked the health of the batteries(good), cleaned the battery clamps, cleaned and re-tightened ground points, cleaned MAF sensor(It was just a tiny bit dirty), re-checked PCV valve and hose, and I changed the fuel filter. Which then some fuel went into my ear. It wasn't fun. But, to look at the bright side, my ears are probably clean AF now.

Symptom still persist. Still stumbling/surging during acceleration. I also noticed that it gradually gets worse when the engine gets hotter. It's still there when driving after a cold start, it's noticeable, but not like how it is when the engine gets properly hot.

Do you guys think it's the ignition coil? is there a way to check if the ignition coil is faulty? I went to autozone to try and purchase the part, my plan was to install it and see if it solves the problem, if not, I was gonna return it. Turns out, they don't accept returns after it gets used. I really don't want to keep blindly throwing parts at it without a proper diagnosis.

 

If you see cracking on any portion of the coil, including the base (removal needed to check), then it's def. on it's way out and needs replacement.

To get a better idea of symptoms, do you get a stumble only when you've just depressed the gas pedal? Or do you have an issue only on constant throttle - or all the time when warm whatever throttle motion.

Constant "miss" is different than a stumble with throttle application in particular.

 

I did check the valve and hose. It seems to be healthy. No cracking or anything. I also checked the "shoulder" of the hose and it's fine. I will check again for good measure sometime this week.

It only stumbles(hesitates) when I press on the throttle and it reaches a certain RPM. I can't specifically point out what the exact RPM range is when this symptom acts up cause the LX doesn't have an RPM gauge. But I know it's not a high rpm. Right now I'm probably shifting up very early. Cause it would start stumbling if I don't. Right now, it is unsafe to take to the freeway. It takes long for me to get into the suitable merging speed.

 

http://www.focusfanatics.com/forum/.../forum/focus-power-tuning/644994-mkiii-full-turbo-kit-pictures-focus-power.html

Coil, not hose - the squarish item the spark plug leads attach to.

DO check it, as increased misfire under higher throttle/RPM is a common sign of one going bad.

BTW - you mention changing plugs, did you check/adj. the gap as required to spec. for the car?

 

Oh my bad. I thought you were referring to the PCV hose. Is the coil you're referring to the one that's connected at the plugs? or the ones connected at the ignition coil? Also, the ignition coil, and the coil pack are two different things right? Please pardon my ignorance. I'm not mechanically inclined.

I will check it as soon as possible. Do I just need to look for cracks? I'll keep you posted.

Regarding the plugs, I bought a set of motorcraft ones. and yes, I gapped it correctly. There's a sticker under the hood of my focus that says I need to gap the plugs from 0.52-0.56. I gapped it at 0.54

 

Got the plugs correct, very good.

Your car has a single ignition coil "pack" that combines two pairs of coils, plus plug wires to the spark plugs & the spark plugs themselves. No other parts there, except the low voltage connector TO the coil pack to provide power/control it.

Electrical testing of the coil pack is often indeterminate, but cracking is a sign of failure and moisture gets inside to damage it further.

 

Got the plugs correct, very good.

aww you're making me blush senpai [:I]

Electrical testing of the coil pack is often indeterminate, but cracking is a sign of failure and moisture gets inside to damage it further.

So this is the ignition coil right?
http://www.amazon.com/gp/product/B001SPVBUO/ref=pd_lpo_sbs_dp_ss_1?pf_rd_p=1944687522&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B0031W3GV4&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=11TAW4WPRN564KDB6Q3Q

And this is the wires that connects from that ignition coil above to the sparkplugs?
http://www.amazon.com/Motorcraft-WR5969-Spark-Plug-Wire/dp/B000BYGJGE/ref=sr_1_4?s=automotive&ie=UTF8&qid=1462755290&vehicle=2003-54-679-113--1--5-3401-1202-1-1---4-0&sr=1-4&ymm=2003%3Aford%3Afocus&keywords=spark+plug+wire+set

The ones I need to check is the tips of the wire? or the tips of the ignition coil? or both?

 

That's the coil pack & ign. wire set - correct as to type, didn't check for match to yours.

Cracking anywhere on that coil pack is an issue, often seen on the base that's invisible when mounted as that's where the sealant is poured in during manufacture (epoxy/liquid plastic).

Wires you just need to be careful when connecting/disconnecting as the wire itself is easily damaged. Handle by plug boots and at the ends by the coil. Actual "wire" is carbon impregnated fiber for resistance to reduce RF interference, not metal on std. ones currently. (old & special ones have actual wire)

 

Okay. I'll check it out this week. Thanks a lot for the help! I'll keep you posted.

 

Just curious, don't remember seeing in this thread so far. How old are your plug wires? I'm thinking back to my Escort that would have acceleration issues whenever the wires were going bad. My Focus was the first car I ever had with individual coils to the spark plugs, any compromise in the spark plug wires can cause your issue, maybe not the speedometer one but your engine stumble and hesistation.

 

I don't know how old the plug wires are. I didn't change it since I bought the car two years ago. I will be inspecting them later this week though.

Also, I've read threads in this forum that describes the same problem, majority says bad ignition coil/plug wires. But some also say throttle position sensor. Do you know how I can check that? Where is it located at?

 

For what it's worth, I would look at replacing them. At the voltage that is sent to the plugs, it doesn't take much to bleed off through a bad spot or not allow the voltagevthrough.

 

You need a meter or an OBD scan tool to check the TPS directly, asking earlier about WHEN it stumbles was a way to check on that by looking for typical results from a bad one.

Bad TPS = no or wrong info on throttle position, so it's more likely to stumble when throttle position is changed (particularly adding throttle).

Sensor is at the throttle itself, throttle body is the intake item where the flapper valve opens & closes to control intake air. ("Throttles" air intake)

 

I can see why you asked that now. I described it the best I can. The stumble only happens when I reach a certain RPM. Or maybe when I engage(open?) the throttle above 40%.

Do you think that's the result of a bad TPS?

 

Both unlikely, that's why I didn't bring it up.

Occasionally it'll give trouble at the most used position where it wears, the total failure is seen when you open the throttle fast & it stumbles as a result. Needs to know about the sudden throttle movement to add extra fuel to compensate.

 

Yeah, it happens still even when I engage the throttle slowly. As long as I reach a certain rpm, it stumbles, at any gear.

By both, you mean TPS and?

 

If you , or someone that you know, have a multimeter, you can check the TPS using by reading the resistance through either end and the center tap. It is a potentiometer that will go through the range of resistance from high to low or low to high depending on which end you check from. If there's a bad spot, which would give a bad feedback to the ECM, it will show up. I checked at a NAPA in your location online and plug wires are from $20 to $30, if you don't know the age of your's it's an inexpensive step to either fix it or rule it out. I only bring it up because it was an issue on an Escort that I had before.

 

UPDATE: stumble issue fixed. YAY!

On Sunday, I took the ignition coils and wires apart to inspect. I couldn't find any visible hints that it is faulty. I did however notice that the plug wires were motorcraft but the ignition coil pack wasn't. It was brandless in fact. That told me that the previous owner replaced it and skimped out by buying an aftermarket one(He did this too with other parts such as the mounts.) So I replaced the plugs wires and the coil pack, and now it drives like it's brand spanking new.

Now, the only issues left are some noise and vibration due to the bad mounts. I already ordered OEM ones, and I shall replace them soon. And the speedometer "ghosting" issue which I have no idea how to fix. Any ideas?

Also, does someone know(or have a part number)of what this hose is called? It's getting brittle and I want to replace it soon. Thanks!

 

That's a PCV (breather type) hose, IDk about availability but anything that fits will work.

You can also replace it with a small breather filter right at the port of the valve cover, and just block off the other end at the air box.

 

I see, thank you!

Btw, I still haven't solved the speedometer issue. The one that happens when my engine warms up, the speedometer starts moving erratically, then at one point, the needle will reach top speed, then when that happens, for 2 seconds, the engine seems to choke, and I could not accelerate. Does this sound like a faulty VSS?

 

Yep, it could be and that can affect engine power.

Always start cheap & check connections.

 

I see. So I was able to record it when it was happening. Here it is:
https://www.youtube.com/watch?v=8mdKri4NurQ

This happens when the engine gets hot. In the video, I was approaching a stop when it happened, and it only stayed at 140 for a second, but sometimes it stays in there for like 3 seconds. When it happens, the engine feels like it's choking out, and I could not accelerate. It happened once when I was merging on the freeway.

 

The Focus has electrical problems that can start at the negative battery connection to the chassis. It's right there by the battery. take the screw off, scrape the paint, dielectric grease and reassemble. I sprayed mine with battery terminal protector afterwards. The entire negative connection is carried through the threaded section of the screw only. This is a terrible design and can lead to electrical ghosting as the connection waffles with corrosion.

 

Just wondering if you ever got the teaching out issue sorted?

 

He probably quit teaching a long time ago.

(I had to, couldn't let it go)