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  • SN95 4.6L Mustang Tech

Got service engine light off by chaning 02 sensors but still misses?

  • Thread starter Thread starter 5spd GT
  • Start date Start date Mar 27, 2007

5spd GT

"the 5.0 owns all"
Founding Member
Aug 7, 2002
9,516
6
99
Arkansas
Mar 27, 2007
#1
  • Mar 27, 2007
  • #1
My car had been missing bad of late and got slowly and slowly worse.

My service engine light had always been on since I have bought the car. I got the codes read and changed both 02 sensors that needed it. It turned the light off on it's own, I didn't have to unplug the battery. The popping got a little better.

The car still misses in the upper rpms quite badly. Really anything past 1/4 throttle and it misses.

I was thinking with all the 'lean popping' I would get that I 'popped' the headgasket. I know my coolant is dirty.

What are possible effects? Bad injector? Coil? Plug?

I'm having it go in the shop in a couple days...just looking for ideas!
 
0

03MaCh1nE

New Member
Oct 18, 2006
84
0
0
Mar 27, 2007
#2
  • Mar 27, 2007
  • #2
what were the codes???
 
D

Dragstr05

New Member
Dec 21, 2004
643
1
0
40
Stafford VA
Mar 27, 2007
#3
  • Mar 27, 2007
  • #3
How long have you driven it since you replaced the O2's?

Driving for so long with the O2's messed up will make the PCM learn really wacky fuel trims. If you didnt erase the codes, try disconnected the battery for roughly a half hour and go drive it again and see if the problem goes away. Your PCM just may need to clear out and learn from a fresh start.

I had a transmission problem once with a really severe 2-3 flare shift, even after the repair. After disconnecting the battery it cleared the memory and the flare shift was gone. Hopefully this method works for you.
 

00GTpony

Member
Mar 10, 2007
162
0
16
Mar 27, 2007
#4
  • Mar 27, 2007
  • #4
See what cylinder is missing, then change coil pack, and plugs. That should take care of the miss
 

Mike97gt

it doe snot
Founding Member
Jan 26, 1999
10,633
7
89
the people's republic of massachusetts
Mar 28, 2007
#5
  • Mar 28, 2007
  • #5
9 out of 10 misifres I see on these cars is a coil/plug/wires problem..

I would start by replacing the plugs and then check your coil packs for cracks.. many times when the coils on the 96-98 cars go bad you will see small hairline crack on the coil pack..

misfires caused by a bad fuel injector or base engine concerns are very rare so I would look at the ignition first.
 

5spd GT

"the 5.0 owns all"
Founding Member
Aug 7, 2002
9,516
6
99
Arkansas
Mar 29, 2007
#6
  • Mar 29, 2007
  • #6
I was thinking, I bet it is the leaking coolant from the engine at the plastic crossover on the non-pi intake? Could it be getting in the plugs/wires/etc?
 
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