2003 Ford Mustang 2003 Mustang gt - Idle & Weak Accel.

JM3945

MEMBER
2003 FORD MUSTANG
V8
2WD
MANUAL
46,650 MILES

Just a few days ago my mustang started to misfire on cylinder #3. When I fiirst start it up it idles fine. If I rev it up it will idle very low and rough like it wants to die and ends up smelling like its running rich. Since then I have changed the spark plugs on all cylinders, changed the oil and filter. I tired a new 'coil on plug' but that still did not help. Every time I scan the computer it either throws random codes, or none at all. Now my oil is milky white on my oil cap but not on the dipstick. Any help would be appreciated before I go to a service shop.

Monday, March 2nd, 2009 AT 4:08 PM

3 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Misfire at no. 3 -check compression and injector for that cyl.

Random misfire P0300 normally points to false air and bad fuel

Misfires can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire), loss of compression, vacuum leaks, anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel.

Also check the PCV system

Was this

answer

helpful?

Yes

No

Monday, March 2nd, 2009 AT 4:30 PM

JM3945

MEMBER
2 POSTS

What about my oil cap having the milky substance on it?

Was this

answer

helpful?

Yes

No

Monday, March 2nd, 2009 AT 5:15 PM

RASMATAZ

MECHANIC
75,992 POSTS

Its probably due to condensation-Check your positive crankcase ventilation valve system. Might want to replace the PCV valve.

If its leaking coolant in the crankcase it will mix with oil and turn into milk shake an dit will show on the stick If in doubt get it block and pressue tested

Was this

answer

helpful?

Yes

No

Monday, March 2nd, 2009 AT 6:05 PM