07 mustang gt engine issues

[Sparrow07]

Hello everyone, I am new to this forum, and my car for that matter and am having some issues I need some help with.
I have a 2007 mustang gt that I bought recently with about 62,000 miles on it. It ran good when I bought it but, the check engine light was on. So, I went and had it read, and it had codes for a cylinder 2 misfire, cylinder 8 misfire, and one meaning the throttle body needed cleaned. So I took the throttle body off and cleaned it, and then decided to pull the plugs and change them. Somehow I got all of the plugs out without any problems, I don’t know what was causing the cylinder 2 misfire other than the fact that it was a little loose; however, it was pretty obvious what was causing the cylinder 8 misfire as when I pulled the plug the tip and electrode where broke off. Now that caused some concern; however, it did not look like it happened recently, and I used a bore scope to look for damage, or any pieces and everything looked normal, so I assumed that any damage that was going to be done had already been done, and it had been ejected. So I replaced all of the plugs, and the car ran great, better than ever for a while.
Then a couple weeks later I started having my current problem, which is, the engine will start having a really sluggish acceleration and what feels like a bunch of hesitation, it also idling very rough, and I can feel the whole car shaking back and forth as if it had a big Lopey cam in it. The exhaust also has this very peculiar smell to it, much different than normal, maybe like a sulfur smell. The engine also makes a really loud ticking noise coming from both sides of the engine. I have tested all of the ignition coils by pulling them out one at a time, and they all changed the idle significantly, so I think they are ok.
And the weirdest part of the whole thing is that all of the symptoms come and go at completely random times. It all started randomly when I was driving one day, and then went away about 5 minutes later and then came back a couple days later and lasted until I shut it off and then came back to it a few hours. Then it ran good for about a week and now has done it again twice today.
So, if anyone has any suggestions on what it might be or what I can check all help is appreciated. I am completely stumped by this problem.
Thanks

 

[stkjock]

Start simple, test the battery and alternator and major grounds. Elecrtonics can make these cars act wacky

 

[Sparrow07]

Alright, thanks for the reply, I will check the electrics out.

 

[Sparrow07]

What is the best way to tes all of the grounds to make sure they are good?

 

[Sparrow07]

I checked the battery and alternator and they were working as they should be, what else could I check?

 

[Dino Dino Bambino]

Perhaps the cats are plugged up. Lift the car up and bang on each cat with your fist (preferably when the exhaust is cold). If even just one of them rattles like a can of marbles, replace both of them.

 

[Juice]

Sulfur smell + rough idle = EGR valve stuck open.

 

[Sparrow07]

Alright, I’ll check those out

 

[eighty6gt]

There is no egr valve

Check your hot oil pressure with a mechanical gauge

 

[Sparrow07]

Yea just found out there is no egg valve after looking for it for like 15 minutes. The car almost sounds like it’s misfiring at idle sometimes also, but then sometimes it’s completely fine

 

[msvela448]

Check for stored codes again.

Ticking from both sides of car... Without hearing it... Could be:

1. Exhaust leak (can go away with a warm engine, especially if the leak is at the header gasket area)
2. Cam gear problem (broken spring on cam gear is a frequent problem)
3. Normal sound of fuel injectors (sound present 100% of the time the engine is on)
4. Low oil pressure (causes VCT problems and / or collapse of the lash adjusters and valvetrain noise).

Rough or changing idle can also be an indicator of a vacuum leak. While you are checking for stored codes you should also watch short term and long term fuel trims.... + / - 5% is normal. Higher values indicate a problem that is often a vacuum leak.

Might as well clean your MAF while you are poking around. Use electrical contact cleaner or MAF cleaner only (not brake or carb cleaner sprays). A dirty MAF can cause all kinds of problems including a surging idle and poor performance and gas mileage.


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[Sparrow07]

Alright, I jacked the car up and couldn’t hear any rattling or anything when hitting the cats. The ticking is all of the time, and I listened with a screwdriver, and it is present on all of the injectors, so I assume it is just the injectors ticking, as far as the codes go I have nothing to read codes, and there are no warning lights, so would there still be any codes if I took it to oreilly’s even though there are no dash lights. I’ll clean the MAF though and see if that does anything. I’m about to the point of just taking it to a local mechanic, although I don’t know if he will be able to diagnose it since it doesn’t happen all the time.

 

[Sparrow07]

Also something I just thought of is, a couple of days before this started happening I was on the interstate and was going full throttle when all of a sudden it was like all power was cut, and the check engine light started flashing, and I slowed down and cruised for a minute or so, and then the light went off. Do you guys think this has anything to do with it?

 

[msvela448]

It is possible for there to be stored codes without the check engine light staying on. O'Reilly should be able to read stored codes. But what City / State are you in?... Someone on these forums might be close by and could help you read codes with a handheld tuner.

What you are describing, with a full throttle blast and having a broken spark plug concerns me that you might have mechanical damage to something (bent valve comes to mind) HOWEVER the poor performance would always be consistent with a bent valve... Definitely not intermittent.

Some other things to check are the crank position sensor and the cam position sensors. They probably aren't physically damaged, but sometimes oil seeps into the electrical connector, particularly at the crank sensor, and could cause a poor connection or impedance issue. Inside them is pretty much just a magnet that senses the reluctor wheels spinning on the crank and cam gears... Hard to damage unless they get struck by a broken or loose part. Just pop the electrical connectors off and spray some electrical cleaner in both ends, blow it dry or wait for it to dry and reconnect. You can do the same with the connectors on the variable cam timing solenoids.

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[Sparrow07]

Alright, I am in central Illinois. And yea the problem only happens every now and then, although it is happening more and more often, I will try some more things you guys suggested here soon and see if it changes anything.

 

[Sparrow07]

So, I just went to oreillys and had them hook up the scanner and got codes P0305, P0316, and P1000. So it’s saying I have a cylinder 5 misfire even though I just changed all 8 plugs when I had the cylinder 2 and 8 misfire. It is also detecting misfire on startup, and saying the drive cycle isn’t completed. So I guess I’ll pull the plugs again tonight and see if there is anything I can see.

 

[Dino Dino Bambino]

Did the previous owner wash the engine prior to the sale? If so, you could have water contamination in one of the ignition coils or injector harness connectors.

 

[eighty6gt]

Gen 2 coyote engines are coming down in price.

 

[msvela448]

Based on this new information. My guess is also a coil pack, or connection to coils (clean those connectors too). There's quite a bit of information on the internet on how to check the resistance of coils with an ohm meter to see which one(s) are bad, and you already have a good start with the computer pointing at #5 (front most pack on the driver side). This also makes sense with the power failure under WOT, and rough idling.

If you need a new coil I would highly recommend a Motorcraft OEM replacement. They have been proven reliable for all types of engine power ranges and should run from sub freezing to desert heat environments. Rock Auto usually has great prices.

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[Sparrow07]

Well, guys, I think I may have found my problem, when I went to pull the plugs to take a look, 3 of them were so loose I could unscrew them with my hand. I torqued them all back down to proper spec, and it has been running great the since. I guess time will tell if the problem comes back or not. But while I had them out, I took that as a chance to use my borescope to look in the cylinders, and on a few of the piston tops there were some specs of rust formed. Is that anything to be concerned about?