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  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

Motor missing under load

  • Thread starter Thread starter Gtwo
  • Start date Start date Jan 26, 2012

Gtwo

Previously 984.65spd
Jan 22, 2012
151
0
17
arcadia florida
Jan 26, 2012
#1
  • Jan 26, 2012
  • #1
My 98 stick car is missing real bad under load and once it starts it won't quit till you shut the motor off and restart it,then it runs like a raped ape. For a minute anyway then it goes right back to its trick.
Kinda acts like its running outta gas, it does have the o2 sensors disconnected when the cats got Removed, any ideas,I got a fuel filter to put on tomorrow, hope it helps.
 

brtnstrns

Member
Dec 19, 2003
606
11
19
Lewisville, TX
Jan 26, 2012
#2
  • Jan 26, 2012
  • #2
I was gonna say O2 sensors. Any chance it isn't tuned correctly for having them disconnected?
 

Gtwo

Previously 984.65spd
Jan 22, 2012
151
0
17
arcadia florida
Jan 26, 2012
#3
  • Jan 26, 2012
  • #3
Just bought the car and really have no idea what its got. It does have a cai, headers and 3" straight pipes with flowmasters, was told it has a cobra intake,and a " stage 2" chip?
Plus bigger injectors, but not sure how to be sure.

Which tuners allows me to "turn off" the o2 sensors?

A local yokel says its the camshaft position sensor?

Would a failing fuel pump act this way?

I thought maybe the pump was sucking something up and when you shut the car off it loses suction and drops it back down. Or a hose pinching flat, is it hardline all the way down to the sock or is there any rubber line between the sock and pump?
 

trombonedemon

Well-Known Member
Jun 25, 2009
1,962
39
59
U.S.A, U.S.A., U.S.A.!
Jan 26, 2012
#4
  • Jan 26, 2012
  • #4
Start doing some tests.

You can check the fuel injectors by what color they are. Use the search function provided.

Are you throwing any codes or have any stored? Get a OBD2 reader or go to Auto-Zone.

My instinct tells me that the Cobra lower intakes don't fit a two valve, the heads have to be swapped over, somebody correct me if I'm wrong.

Check fuel pressure. Check spark-plug wells and check spark plugs for coolant. Check cylinder head compression. Check gaskets for leaking coolant and the plastic coolant crossover.

Could be a lot of things that are wrong. Sometimes symptoms are the same for failing car parts.
 

Gtwo

Previously 984.65spd
Jan 22, 2012
151
0
17
arcadia florida
Jan 27, 2012
#5
  • Jan 27, 2012
  • #5
This is what the top end looks like.
 

SROBERTLAW2003

Member
Jan 27, 2004
109
0
16
Orange beach alabama
Jan 27, 2012
#6
  • Jan 27, 2012
  • #6
did you buy this car from a guy out of scottsboro alabama?
 

Gtwo

Previously 984.65spd
Jan 22, 2012
151
0
17
arcadia florida
Jan 27, 2012
#7
  • Jan 27, 2012
  • #7
No,came out of south Florida.

Drove all day today with never a sputter one,didn't get enough downtime to change the filter,but for sure in the morning. Want to get this bug out so I can put my spray on it.
 

trombonedemon

Well-Known Member
Jun 25, 2009
1,962
39
59
U.S.A, U.S.A., U.S.A.!
Jan 27, 2012
#8
  • Jan 27, 2012
  • #8
You have the 19lb fuel injectors.
 

Gtwo

Previously 984.65spd
Jan 22, 2012
151
0
17
arcadia florida
Jan 29, 2012
#9
  • Jan 29, 2012
  • #9
Ok,put New filter on, kinda brownish looking gas coming out of it, runs clear in the line though.

Fuel pump is getting replaced for good measure, its already making some weird noises, not gonna wait for it to leave me stranded.

My next question is this, I have the 98 gt with a return line. It just has gears,lt and full exhaust with a cai for now, but cams and no2 are in its future. What fuel pump is the cheapest that is up to the task, is the walbro 255 the right pump for my application? Any suggestions would be greatly appreciated.
 

AZmustang98

Member
Oct 19, 2011
373
17
19
Flagstaff, Arizona
Jan 30, 2012
#10
  • Jan 30, 2012
  • #10
I think other than SVT Focus pumps and some other OEM Ford pumps. The Walbro is the only "aftermarket" pump and it flows 255...

Correct me if im wrong.
 

Gtwo

Previously 984.65spd
Jan 22, 2012
151
0
17
arcadia florida
Jan 30, 2012
#11
  • Jan 30, 2012
  • #11
Got these codes

P0340

P1150

P1151

P1152

P0420
 

OonDeanisS

Founding Member
Jun 16, 2002
902
1
19
Danbury, CT
Feb 11, 2012
#12
  • Feb 11, 2012
  • #12
did you resolve this issue? i have a similar problem on my 1990 5.0.
 

98gtDan

Member
Feb 7, 2012
48
0
6
texas
Feb 11, 2012
#13
  • Feb 11, 2012
  • #13
P0340 is the Camshaft Position Sensor and are around 15 dollars.
the rest are from the lack ok o2 and cats.
 

OonDeanisS

Founding Member
Jun 16, 2002
902
1
19
Danbury, CT
Feb 12, 2012
#14
  • Feb 12, 2012
  • #14
and i quote, from LRS... "Some symptoms of your Mustang's camshaft position sensor failing are: engine dying at random, check engine light coming on, engine will turn over but not start, dying at stops, or the engine will crank but will not start back up."
 

Gtwo

Previously 984.65spd
Jan 22, 2012
151
0
17
arcadia florida
Feb 12, 2012
#15
  • Feb 12, 2012
  • #15
This seemed to fix it.
 

evolucion311

Member
Mar 19, 2009
236
2
18
Feb 12, 2012
#16
  • Feb 12, 2012
  • #16
 

OonDeanisS

Founding Member
Jun 16, 2002
902
1
19
Danbury, CT
Feb 12, 2012
#17
  • Feb 12, 2012
  • #17
 
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