Alexi

Hi guys, I have a 05 gt std with 111,000miles on it. It runs awesome but sometimes when I come to a complete stop it starts knocking. I get scared and turn it off and I imediately turn it back on and the knocking is gone. Any ideas, has to me twice already. Once after a burn out. So I guessed it was that but the other time I was not fooling around with it. Just regular fun cruising and when I came to a complete stop it started knocking. Again the wierd thing is that you shutoff and restart the engine and its gone.. im scared. Thanks in advance.

m05fastbackGT

When was the last time you changed the spark plugs and fuel filter? If it's been quite awhile, I'd start there first

Alexi

Thanks for the reply I bought this used like maybe to months ago so dont really know. All i have done is change the oil. Going to get it scaned today, fingers crossed. Car has since been running fine. Wierd one huh!

Paris MkVI

A full service on a used car happens one of two ways:

[1] Previous owner has the car fully serviced, and bumps the price to cover it. You pay for it.

[2] Previous owner does not have the car fully serviced. You buy it and figure out what has or hasn't been done. You pay for it.

No service records handed to you when you buy the car? Assume the worst.

m05fastbackGT

Couldn't agree more

Cavero

Check engine light on? Any codes?

I've heard of getting a bad tank of gas causing issues like that. Has it been going on for more than one fill up?

My other thought would be cam phasers...they're known to be weak on the modular motors and can start failing around the 100k mi mark.

Anything like this?

Alexi

K guys I got it scanned no codes except for the o2 sensor due to headers and piping. The mech said that it seems that the ignition coils are starting to go. He said I should start there scince he pulled some spark plugs and they seemed pretty new.
I already order ignition coils for my f150 so I will try them on the car and rescan. If it scans better then just buy new good coils maybe msd. My first rhought was also the phazers but lets start with the cheapest this first. Fingers crossed.

Alexi

Omg!! Thats it! Well sounds pretty dam close.

m05fastbackGT

You would think the mech would know for certain as to whether or not it's ignition coils. What about having diagnostic testing done at your local dealership to make certain

Alexi

He did say for sure the coils are bad or atleast show up on the scanner as bad. But the car isnt sputering or anything.

Cavero

If it's making noise at idle and goes away when your revs go up, it sounds like that may be your culprit. To get a better idea if its really the case, try to figure out if the noise is really coming from them or not. The phasers are under the valve covers at the front of the engine. Try to listen to see what side it's coming from. You can use a mechanic's stethoscope if you have one, or I've even used a screwdriver. Just put the pointy end on the valve cover and put your ear on the end of the handle (and not the other way around ). Move it around and see if you can pinpoint it coming from the front of the valve cover on one side or the other.

m05fastbackGT

I stand corrected, as I misinterpreted. So if he said the coils are definitely bad, then I would start there. I'd also follow Cavero's recommendation about the cam phasers as well