Focus Fanatics Forum banner

1 - 20 of 23 Posts

·
Registered
Joined
·
129 Posts
Discussion Starter #1
I recently replaced my valve cover gasket because it was leaking badly. The person who installed it torqued it down way to tight (FINGER TIGHT ONLY!!!) So I had to redo it.

Since I pulled the cover off I decided to run a fuel injector cleaner in case any dust or other schmegma got knocked into the valves.

Car ran great for about a day then disaster ..... During take off she sputters at low rpm and when under load BADLY. But the idle seems alright. At highway speeds she'll sputter and hesitate like she isn't getting enough fuel when under WOT after a downshift. This is all at random, it isn't every time, but it's often. So I thought the reasonable thing and figured I dislodged something and its causing an injector to fowl, line to be clogged, ect. Starting at the simplest and cheapest solution I replaced my fuel filter (it needed to be done anyways). No leaks, it's is done right, to no avail.

I poured over all the information I could find on this problem. What gets me is that there isn't a CEL or other indicator being thrown. If it were an injector ,or a plug ,or a wire ,or clogged cat it would throw a check engine light. If it were a fuel pressure problem it would give me a fuel cap or CEL light. If it were mechanical or electrical like a TPS I would be able to reproduce the same outcome constantly.

I have read that a fuel pump failure does not throw a CEL. Is there any other problem that could cause this with out throwing warning lights?

My VCT is leaking a little but I think it is just the O ring. Plus if the solenoid were frozen then it would also affect idle as well and idle seems to be for the most part, ok.

PLEASE HELP!
 

·
PARTS HUNTER
Joined
·
3,001 Posts
Push on all the connector pigtails under the hood. Push on all the spark plug wires on the plugs and the coil pack. U could have knocked something lose and it gets worse when u torq the motor/load.
 

·
PARTS HUNTER
Joined
·
3,001 Posts
Check the pigtail on the coil pack too
 

·
Registered
Joined
·
129 Posts
Discussion Starter #4
I already tried that as well as making sure that the plug wires were away from any other electrical wiring ( as much as possible). Nothing is loose. I got her up to 125mph this morning and she sputtered a few times on the way up but she got there. I thought if I did have a partial obstruction I may be able to blow it out. Nope... she is still sputtering at random. But never under idle.
 

·
Registered
Joined
·
129 Posts
Discussion Starter #6
It only threw one code when I depressurized the fuel system (unplugged the fuel pump fuse and let the car run till it died). After I was finished replacing the fuel filter I disconnected the negative battery terminal and let it sit for 5 min while the ECU reset. Once reconnected there hasn't been another CEL and the engine still acts the same.

So..... no codes and just did, trying to fix the problem.
 

·
Registered
Joined
·
994 Posts
pull your plugs, might be a cracked/fouled plug. Mine does this every once in a while when trying to drive it hard w/out letting it warm up.

If it's the case, just keep an extra set of plugs in your garage...

PS> I'm glad your still liking my old hood, i want my TB back!
 

·
Registered
Joined
·
129 Posts
Discussion Starter #8
I think if it were a plug it would be more consistent, but it is so random. When it does happen it seems the more throttle I give her the worse it gets. Stuck in the waiting room at the court house for jury duty.FML.
 

·
what it be like
Joined
·
6,381 Posts
you said you had the valve cover off..did you make sure the vct is on there good..has to be something small maybe coil or vaccum leak
 

·
Registered
Joined
·
129 Posts
Discussion Starter #11
I did make sure the VCT is on properly. the "O" ring is leaking a tad but the soleniod seems to work fine because it idles ok. FACEPALM.

Any other ideas? Keep in mind I have no check engine light, the car idles fine, it only happens under load and it seems to be vary random both in severity and frequency.
 

·
PARTS HUNTER
Joined
·
3,001 Posts
I had frayed wire onthe pigtail to the coil. It would mess up once I got on it hard or shifted hard. Even tho u checked to make sure the connections are clipped check the wires going into the plug
 

·
PARTS HUNTER
Joined
·
3,001 Posts
I had a weird misfire also it turned out to be a blown piston. Cylinder #3. Couldn't hear it till it had a load on it.
 

·
Registered
Joined
·
994 Posts
I think if it were a plug it would be more consistent, but it is so random. When it does happen it seems the more throttle I give her the worse it gets. Stuck in the waiting room at the court house for jury duty.FML.
I ended up getting a lease on another car, and just saving the SVTF, it has so low miles, I might as well just sit on it and use it as a spare.

But I had the same problem, riddle'd down to the ignition system, because I had already changed the fuel filter and cleaned the injectors. Honestly check your plugs and their gapping, every time this happened it was one of them, and the white part of the plug would be cracked which cause it to foul out intermittently until the car warmed up. So I just bought another set of plugs and ordered a new OEM coil and wires off eBay for like 45 shipped. And make sure your plugs are gapped correctly, gapping them to far will cause thite part of the plug to crack too.

If this isn't the problem for you, then check your primary O2 sensor, if you motor was going back, you would have a constant lose of power and miss fire. So don't worry, whatever it is, it's a simple fix.





Posted via FF Mobile
 

·
PARTS HUNTER
Joined
·
3,001 Posts
Im just saying don't thrash on the car(wot-high rpm downshifts - stress ) till u figure this out.
 

·
Registered
Joined
·
129 Posts
Discussion Starter #18
OK. The problem turned out to be (drum roll please)...... a cracked plug. I went to my performance mechanic, who was finally at his shop and described my problem. He said bad plug after about 2 sec of thinking, (ignition is his primary specialty) and scolded me for using a cleaner when using AMS Oil. He handed me a socket and told me to pull my plugs. Low and behold the #4 plug had a tiny crack that looked more like a scuff on the porcelain. It was almost too small to see. We called the car parts delivery service and they rushed over a new set, put them in and BOOM! she is back to the same old grunty self.

You were right Blackjack. I owe you lunch buddy.
 

·
PARTS HUNTER
Joined
·
3,001 Posts
Use the one step colder coppers. Just change them every 10k. $8 a set
 

·
Registered
Joined
·
129 Posts
Discussion Starter #20
I was using Nology silver core. They lasted 20k+. I might be going with them again but they are a bit pricy at like $7 each.
 
1 - 20 of 23 Posts
Top