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-   -   Car running lean, any suggestions? (http://forums.mustangworks.com/showthread.php?t=36987)

MATTKNIGHT 06-06-2003 01:43 PM

Car running lean, any suggestions?
 
Okay, guys, I will start by saying sorry if this is long winded. I want to give an accurante account as to whats going on. I have a 95 gt, 72000 miles. I installed long tubes, off road h pipe, flows, cold air, msd 6al, new distributer (oem replace), msd coil and i think thats ablout it. I ecountered a problem a few months ago when my car started running lean. I checked my fuel press- 36psi @ idle. I replaced my o2 sensors hoping it would help, to no avail. I replaced my fuel filter and got nothing. I cannot figure out what the prob is. I checked every chilton/haynes type manual for help and got nothing. I am kicking a soft fail check eng light. It comes on during heavy accel. Downloaded the fault and got "left bank running lean" and "right bank running lean" as well as an "egr" code. The only modification that was not a direct bolt on was the headers. Everyone knows how they interfere with the smog lines in the pass side eng bay. I reset the comp numerous time as well as checked and reset the timing at least 7 times. Please help me, my car lost so much power in the 3800 - 4500. There is a signifigant loss in power throughout my rpm range as well. My great running car is giving me a headache. I got beat by a Honda the other week. I need help... :mad:

Stang_Crazy 06-07-2003 04:02 PM

Was the 36 psi at idle with the vacuum line DISCONNECTED?

If you have an adjustable fuel pressure regulator, try bumping the FP up to 39-40 psi at idle with the vacuum line disconnected.

drtbiker 06-08-2003 06:38 PM

maybe a weak fuel pump if not make sure u adjust the fp with the vac line off. Did u look at ur plugs?? How do they look.


later

Coupe50h 06-09-2003 01:13 AM

My plugs indicated my car being lean, finally the car started stalling recently, today i pulled the fuel filter (Which wasnt very old) and it was so clogged! i replaced it today and it idles real good, and no stalling so far, i realize you replaced yours, but never can do it enough, my tank is obviously full of crud, plus i always run the tank low.:o
hope you fix it.

MATTKNIGHT 06-09-2003 08:22 AM

More info
 
Hey, just to give you guys more info...
My spark plugs are definitely white, running lean w/o doubt. My fuel pressure as stated above was with vacuum connected. Replaced my fuel filter AGAIN and still haveing problems. Ford tells me they wont work on it because I have modified the car. Dont understand what they're deal is. I just want this damn thing fixed. Any more ideas from you guys would be greatly appreciated. Thanks.
Matt--

Stang_Crazy 06-09-2003 05:43 PM

Disconnect the vaccum line and set your fuel pressure to 38-40 psi. That should solve the problem...take the car out and run it for a while. When you get back home, check your plugs. If they're white, try bumping the fp up a few more psi.

SilverSN95 06-09-2003 09:27 PM

I can only add my 2 cents from past experience with my old 86 GT. I had a lean running condition with it once that turned out to be a leaking EGR valve. If I remember correctly (this was about 10 years ago), the car just didn't want to run smooth. I ran the codes and the 'running lean" codes came up. As a trick I remember spraying the egr (diaphram) with water and the idle smoothed right out. Replaced the EGR and all was good.

Hope this helps

MATTKNIGHT 06-11-2003 08:11 AM

More info yet....
 
Alright, just to make sure it wasnt my fuel press I checked it w/ vaccuum discon. I read 39 psi at idle. Seems to me this should be good. I am getting fed up with the car so last night I started working on it. I took the top end of the motor off, including the heads. I saw no problems, even replaced all the gaskets to be sure no probs would occur. There is a crossover tub on the back of the heads, I plugged the heads instead of reinstalling the tube. During reassembly I decided to ditch all the emissions **** on the pass side of the eng. (down by the headers) I left the smog pump on and didnt plug it. The EGR is just flowing free. I plugged the vaccuum lines running to all the valves associated with the emissions stuff. After finishing everything I take the car for a drive. It fell flat on its face, stumbling like a maniac anywhere above 2800 RPM at wot. I am pissed. I cant get this thing to run right. PLEASE any more advice?? I am on the verge of selling this POS and buying an 03 Cobra.
:mad:

strokedandchoked 02-13-2009 07:04 PM

Re: Car running lean, any suggestions?
 
ok, i have a 95 gt, 437 stroker, msd ignition, bbk CAI, the whole nine yards. I ran into the same issue you are and I went through all the ins and outs of changing my plugs, fuel pump, filter, lines, injectors, everything! Then i finally took it to a shop and had them run a comptression test and found out that i was running 15.1.... with that they re-mapped the ecu which was already chipped and programmed. if you have chipped it, the 94 and 95 5.0's tend to become retarted, in a timing sense once you think you have completed tuning. Reseting your computer doesnt keep the ecu from acting up once its already being dumb. Try finding a professional tuning shop, preferably a race performance/ racing shop and have them re-write your fuel curve. IF your car still runs lean, replace the ecu with non OEM one and see what that does. Everyone who owns or has owned a 94 or 95 has run into this same problem time and time again. Good luck and let me know how it turns out.

USMC302 02-25-2009 10:48 AM

Re: Car running lean, any suggestions?
 
This is a pretty old post, glad you worked your issue out though.

lees gt 03-08-2009 03:52 PM

Re: Car running lean, any suggestions?
 
Matt,what was the problem in the end? I'm running a bone stock 94gt in the UK with the same problem..i've tried everything except the ECU.
Regards Lee


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