2004 Mustang Cobra Cylinders 5 & 7 losing compression

CobraMom · 10-30-2007

I have 80K on my 2004 Cobra Convertible. I took it in for a tune up because it was misfiring. After replacing the plugs and wires, it continued to misfire. An electronic compression scan was completed and cyclinders 5 & 7 are losing compression. A manual compression test and leak down test will be completed tomorrow. Has anyone else experienced this or have any thoughts?

Racman · 10-30-2007

Hmm same side you think maybe a head gasket or warped head?

markwondi · 11-01-2007

Does not suprise me. First off, those are very hot cylinders, as Ford did not route any coolant to those cylinders. Secondly, with such tight PTW clearance, your side skirts are wearing heavily.

Welcome to owning a Ford built 4.6L

CobraMom · 11-01-2007

Yes, same side. In fact the manual test showed 8 was at 120lbs so losing compression as well. Will know more on Tuesday, because it will be taken apart to really see what is in there.

hydro · 11-10-2007

Quote:

Originally Posted by CobraMom

I have 80K on my 2004 Cobra Convertible. I took it in for a tune up because it was misfiring. After replacing the plugs and wires, it continued to misfire. An electronic compression scan was completed and cyclinders 5 & 7 are losing compression. A manual compression test and leak down test will be completed tomorrow. Has anyone else experienced this or have any thoughts?

A leakdown will determine whats going on in those cylinders,look inside the radiator for any "brown foam" to see if the head gasket is blown.Aside from that the leakdown will tell you all thats going on.hydro

bluepony03 · 12-05-2007

my 2003 mach 1 is having the same problem right now...it kept getting a P0305 code(misfire in cylinder 5) so I replaced the plugs and ignition coils but that wasnt it. I have also been losing compression cylinders 5 and 7. my engine is actually being pulled out right now to remove the head.

bluepony03 · 12-14-2007

ok well i just got may car back...turns out my valve seals were not airtight and were leaking air which was causing the misfires. the only solution was a brand new cylinder head...not to mention replacing the head on my car requires the whole engine to be pulled out...on my car this equaled about 3,800 for the entire repair

hockeymaniak88 · 12-15-2007

my brother had the same exact problem in his 01 GT and spent about the same for the repair. Just curious as to how much how you bill was solely labor cost?

bluepony03 · 12-18-2007

it was about $1500 for parts....about $2200 for labor...and of course thats without taxes

and hey thats a really clean GT you got