Pony is running rough

[AboStangster]

Hi all,

I have an 05 GT convertible 4.6L with cold air intake and fairly stock engine wise which. It ran well before going into hibernation for winter, covered, in a dry, heated garage. It had a full tune-up before winter and ran fine after.

I put the battery in, I've changed the oil, oil filter, checked the usual suspects for mouse nests just in case. Its now running rough, even after taking it for a good ride. Its not tyranny, its engine lag and just feels less responsive/rough.
Ideas or thoughts on Hotshot Secret Stiction or Seafoam as being helpful?

Hi all,
More info. I should have said that I have no codes being thrown up.
I changed the plugs last season and all was fine after. I just checked them this season and they are all good.
Thanks all.

 

[07 Boss]

Need more info. Does it run crappy all the time? accelerating? coasting? cold start, warm start, any smoke? what is your exhaust like? have proper oil pressure? have you swapped out the fuel? have you checked and cleaned injectors? Have you pulled the plugs? vacuum leak? bad fuel? reloaded the tune? Can you data log? Could be a million things, unless you help us narrow it down you will get a million different responses.

 

[AboStangster]

Hi
Thanks for the guidance, I will try to provide as much info as I can.
Compared to before winter, it seems rough all the time, more noticeable at lower rpms; almost like when the timing is just a little off on my 1960 Austin Healey. There is no smoke or colored exhaust. The oil pressure is good, temperature is good, fuel filter is clear, I filled the tank with new fuel before taking an hour drive. I have the stock tune. No vacuum leaks or O2 codes with my ODB scanner.
I have not checked my injectors, but did add injector cleaner with my fuel fill up but it made no difference.
Thats all I can think of right now.
Cheers,
Rick

 

[Dino Dino Bambino]

You may still have bad residual gas in the tank. The injector cleaner will definitely help but you probably need more drive time to "clear the cobwebs". I suggest you run the tank down to less than 1/4 and give it a second treatment with fuel system cleaner the next time you refill it.

 

[Juice]

If it is truely running rough, or misfiting, it is just a matter of time before a code will set. You may already have a pending code now. Not all scan tools show pending codes.
Or it is a.mechanical issue not fuel/ignition related and that would not set a code.
Does it run rough all the time? Does it get worse with increased rpms? Increased vehicle speed? Maybe as simple as "flatspotted" tires. Softer tires tend to do that if they sit parked for more than a few days.

 

[86GT351]

How long did it sit? What did you do for fuel? Bad gas can be a culprit for sure. Along with a Fuel Filter

 

[AboStangster]

Hey all, thanks for the great suggestions. The car sat from October to April on jack stands. I added fuel stabilizer before putting away as I normally do. I will run out the rest of my gas today and repeat the injector cleaner with the 2nd new tank of gas. It seems to run a little better. I'm thinking maybe it was the old gas or moisture in the tank from sitting. Maybe the injector cleaner and new gas may be helping and the cobwebs are blowing out. I will keep you all posted.
Again thanks for sharing your knowledge, this forum is fantastic.
Rick

 

[Juice]

Fyi, I dont notice any issues with gas getting old till it has been more than a year. At two years of sitting, I could definitely tell my bike had some hesitation. Completly cleared up with a fresh tank of fuel.

 

[AboStangster]

Hey all. I replaced the fuel filter even though it looked fine and on the 2nd tank of gas and injector cleaner. The car is running much better and the lag is gone.
Thanks for your sharing your knowledge.
Cheers,
Rick

 

[Robert Larimer]

Hey all. I replaced the fuel filter even though it looked fine and on the 2nd tank of gas and injector cleaner. The car is running much better and the lag is gone.
Thanks for your sharing your knowledge.
Cheers,
Rick

Try cleaning you MAF sensor maybe it has cobwebs. It is worth a try.

 

[AboStangster]

I'll take a look. Thanks

 

[AboStangster]

Hey all,

I just wanted to close the loop on the thread.

After changing the fuel filter, running through the second tank of gas and injector cleaner, my Stang is now running strong an back to normal.

Thank all for sharing your wisdom. I learn a lot from this forum, it awesome.

Cheers,
Rick