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Rich and Lean at the same time?????

  • Thread starter Thread starter 98yellowstang
  • Start date Start date May 25, 2003
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98yellowstang

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Feb 15, 2001
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On the Road
May 25, 2003
#1
  • May 25, 2003
  • #1
P0430
P1130
P1150
P1151
P1152

Symptoms:
Part throttle bucking around 2k RPM
After hard run to anything over ~4500 RPM the RPM's will flucuate until it levels at idle ~700 RPM or stalls. Will rev to 1500 and down to 200-300 RPM

The Car has new:
Plug wires, plugs, fuel filter, front o2's, injectors that have only 26k on them.

It is burning gas like its going out of style. Its so rich when I pull into a light I can smell raw fuel wafting back into the windows!!

Any help would be greatly appreciated.

Thanks
Jason
 

patman0911

Founding Member
Jun 5, 2002
2,287
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46
Tuscaloosa, AL
May 25, 2003
#2
  • May 25, 2003
  • #2
Vacuum leak?

It may be running in limp mode now, that would explain the overly rich condition.
 

98yellowstang

Founding Member
Feb 15, 2001
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May 25, 2003
#3
  • May 25, 2003
  • #3
Vacuum Leak? A lot of people have mentioned this. I will check into this tomorrow.

Anyone else care to comment.

Thanks Pat.

Later
Jason
 

invertmast

Founding Member
Dec 12, 2001
379
0
16
North Port, FL
May 25, 2003
#4
  • May 25, 2003
  • #4
My first guess would be vacuum leak,get some carburator cleaner in an aerosol can and spray around the gaskets (intake to heads, TB to upper intake, etc) if it speed up you've gotta leak. If nothing there, if you can get your hands ona new intake, i'd try swapping that, might have cracked it in the motor swap if you just recently finished the swap.... then maybe something more in-depth like.... blown headgasket between the cylinders?

Thomas
 

98yellowstang

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May 26, 2003
#5
  • May 26, 2003
  • #5
well I sure as hell hope its not a cracked intake. Spent way to much money getting this thing running again to just put it back in the garage. oh well maybe I will just sell it as it sits and buy something else haha.

Later
Jason
 

forpit2000gt

Founding Member
Jun 30, 2002
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Columbia, SC
May 26, 2003
#6
  • May 26, 2003
  • #6
what kind of MAF and is it plugged up good?
 

98yellowstang

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May 26, 2003
#7
  • May 26, 2003
  • #7
Stock and I do believe it is plugged in well. I will double check.

I reset the computer today and it is running much better. But after only 1 complete drive cycle the CEL is back on.

Later
Jason
 

99GrandTouring

Founding Member
Jul 30, 2001
1,748
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West Virginia
May 27, 2003
#8
  • May 27, 2003
  • #8
Just curious, if I were to go to autozone and hook up thier scanner to the car, eventhough the ses light isn't on would it show any "hidden" codes??

or if I were to drive down the road would it show any codes that happen only momentarily?
 

forpit2000gt

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Jun 30, 2002
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May 27, 2003
#9
  • May 27, 2003
  • #9
same symptoms on a friends car last week. turned out to be bad MAF sensor. he replaced and no problems since. what size injectors do you have. is the MAF for those injectors?chipped?do you know someone you can switch MAF to test with?
 
H

Highroller

Founding Member
Oct 18, 2002
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Vegas
May 27, 2003
#10
  • May 27, 2003
  • #10
1151 and 1152 are the codes I got when I took off all my Cats... maybe part of it is your 02's?
 

98yellowstang

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May 27, 2003
#11
  • May 27, 2003
  • #11
Everything is stock from the intake forward. Its got stock 98 fuel system and ignition. Stock injectors and MAF. Also the computer is stock as well.

I checked for vacuum leaks and there seems to be none.

The only resolve I have got so far is that I rest the computer and it is running a hell of a lot better. Not using anywhere near that amount of gas and the idle is fine. Which brings me to think its a sensor????

Any other help.

Thanks for the comments guys.

99: As far as I know The basic AutoZone scanner is pretty much useless for what you are explaining. I think you need a higher end scanner. The autozone scanner is good enough to just scan stored codes.

High: The P0430 and P0420 are catylist under efficency as well. I am not worried about that I am worried about the 1130, and 1150s.

Later
Jason
 

forpit2000gt

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May 28, 2003
#12
  • May 28, 2003
  • #12
sometimes resolving problems with codes you can fix will fix other problems. what lb. injectors do you have?
 

98yellowstang

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#13
  • May 28, 2003
  • #13
Stock 19lb/hr
 

invertmast

Founding Member
Dec 12, 2001
379
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16
North Port, FL
May 28, 2003
#14
  • May 28, 2003
  • #14
I used to work at a ford dealership and had a MAF sensor go bad on my car. We unhooked the MAF and drove the car and thats how we determined the MAF was bad. Try unhooking the MAF, it puts the computer in "limp home mode" and see if it runs any better. You might also want to try unhookin the Inlet temp sensor too at a different time, i've seen those do some crazy things before too.


Thomas
 

98yellowstang

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#15
  • May 29, 2003
  • #15
I will check into that as well.
 

forpit2000gt

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Jun 2, 2003
#16
  • Jun 2, 2003
  • #16
is it fixed???
 

98yellowstang

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#17
  • Jun 2, 2003
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Nope.

Started a new trick on the way home from work tonight. sputters when I am on the gas when I get off of it, it idles down real quick in a half miss half sputter way. Very hard to explain. Like when I am on the gas its fine and anything else it just falls on its face when I am not on the gas.

Who knows.

I am going to try to tinker with it tonight.

Later
Jason
 

forpit2000gt

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Jun 30, 2002
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Jun 3, 2003
#18
  • Jun 3, 2003
  • #18
I still believe you need to get someone elses MAF and try it. See what you can get from a junk yard. the problem is very close to what I've seen recently.
 

98yellowstang

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Jul 14, 2003
#19
  • Jul 14, 2003
  • #19
First of last week I put a ProM MAF on the car. It was used but still in excellent shape. All this did was move the bucking to a different RPM now at like 1100-1200 it really bucks. And it seems like its down on power throughout the whole rev range. It hasn't stalled yet. But it doesn't matter the weather now it will buck anytime.

Any more ideas?

Later
Jason
 

forpit2000gt

Founding Member
Jun 30, 2002
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0
Columbia, SC
Jul 15, 2003
#20
  • Jul 15, 2003
  • #20
is the ProM for 19lb hr injectors? have you checked the TPS voltage? is the check engine light on now? did you reset the computer after installing MAF?
 
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