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Spark knock ?

4K views 15 replies 8 participants last post by  scottydsntknow 
#1 ·
Ok so I got a 04 GT automatic...and this past week while driving to work and other places I noticed a metal tin can rattle noise under the stang or in engine bay.....rattle isn?t there wen in neutral and reving.....only wen placed on drive and acceleration....especially wen going up hill stepping on it......but rattle isn?t always there .....could This possibly be a spark knock/detonation ? What parts should be replaced? Gt has full exhaust except for headers
 
#3 ·
Yep, loose heat shields on cats would be the first place I'd look. If its actually detonation I wouldn't drive the car and tow it to a tuner to fix it.
 
#6 ·
Thanks for the replies. I really doubt it?s the heat shields , if it was I would have heard the rattle the whole driving trip, it?s only heard under heavy load or when accelerating uphill......no it?s not tuned I have k&n fipk 2, BBK 78mm tb intake, doorman intake, 2 cats, dumped. Yesterday I upgraded to 91 grade fuel, changed fuel filter , put half a bootle of sea foam..will run sea foam thru intake and oil today after work.....last tune up was made around August(oil,plugs,oil filter)........I have 1 code which is for a bad o2 front sensor, but tht code has been there since I owned the GT so I also doubt is tht.....any ideas on what I should replace ? I will change trans,engine,differential oil and spark plugs this Saturday ... here?s a pic of the beast !
 

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#9 ·
Thanks for the replies. I really doubt it?s the heat shields , if it was I would have heard the rattle the whole driving trip, it?s only heard under heavy load or when accelerating uphill......no it?s not tuned I have k&n fipk 2, BBK 78mm tb intake, doorman intake, 2 cats, dumped. Yesterday I upgraded to 91 grade fuel, changed fuel filter , put half a bootle of sea foam..will run sea foam thru intake and oil today after work.....last tune up was made around August(oil,plugs,oil filter)........I have 1 code which is for a bad o2 front sensor, but tht code has been there since I owned the GT so I also doubt is tht.....any ideas on what I should replace ? I will change trans,engine,differential oil and spark plugs this Saturday ... here?s a pic of the beast !
Fix the known problems first. :facepalm:
 
#10 ·
The front / upstream O2 sensors regulate the air / fuel ratio inbrelation to the signal provided by the MAF. If the upstream O2 is not working, or sending the incorrect signal, the ECU will dump fuel into the system. The engine will run rich, foul plugs prematurely (which can cause spark knock), waste fuel, etc.
 
#13 ·
So I just ordered the 02 sensor from 1a auto.....I also changed differential oil, engine oil, fuel filter and still running 91 grade fuel.seems to idle smoother and throttle response is much better...tomorrow I will do trans oil change and buy new plugs....is there any other part that I can change to make the spark knock disappear? I drove all this week and the rattle wasn?t heard, probably cause I haven?t gone uphill yet. Should I upgrade to accel super coils ? Should I run an oil addative? Royal purple fuel treatment, keep seafoaming thru intake and fuel? Is tunning my only option ? How much does that go for ?
 
#14 · (Edited)
Hopefully you didn't order Bosch units. If you did, return them. Motorcraft or NTK ONLY.
 
#15 ·
No I always go with motorcraft ones. This Friday I'm getting an off road x pipe installed along with new o2 sensors . So I should be able to rule out loose heat shields and bad o2 sensors. hopefully that does it cause I'll be lost after that........I also noticed I have a leaking oil pan gasket.....
 
#16 ·
Torque the oil pan bolts in sequence to the proper torque. The gasket is re-usable and a lot of the time the bolts just get loose.
 
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