1998 cobra check engine light on running lean

pvtdiaz · 09-26-2009, 07:15 PM

I have a 1998 cobra when i bought it the check engine light would come on for a while and it would idle high like 1500rpm it would take a long time to go back to normal idle then the check engine light would turn off its been six months since now the check engine light stays on and i have the same idle problem when i drive the car agressivly only i had the codes read it says its running lean in bank one and two i had a technician diagnose it and he said it was a leak in the rear of the lower intake manifold. so is that possible? is there any aftermarket lower intake manifolds? any help would be appreciated.

SuperG · 09-28-2009, 08:53 AM

I wonder if you could also have a bad O2 sensor(s)...hopefully someone smart will chime in!

nckissfan · 09-28-2009, 08:56 AM

I second the bad 02 sensor

pvtdiaz · 10-01-2009, 03:53 PM

i changed the two front ones with brand new bosch ones and the two rear ones are denso's they look good

**cobrabitn** · 10-01-2009, 09:25 PM

Well, that's possible but I would check other items first before I went into taking the intake off or apart.

1. Check the idle position sensor for proper setting
2. Check to see if the MAF sensor is clean and doesn't have dirt on it.
3. You don't really tell much about that car, is it stock or are there headers on there? Could you have a vacuum leak prior to the sensor in which it will make it seem like it has a lean condition when it doesn't?

pvtdiaz · 10-02-2009, 08:08 PM

well i took the car to the ford dealer they finally found the problems it is a vacuum leak from the intake but also they told me i am going to need the imrc plates so i was wondering if i should delete or replace them with new ones and if anybody know any mechanics in the los angeles area

09-26-2009, 07:15 PM	#1
pvtdiaz Registered User Join Date: Sep 2009 Posts: 4	1998 cobra check engine light on running lean I have a 1998 cobra when i bought it the check engine light would come on for a while and it would idle high like 1500rpm it would take a long time to go back to normal idle then the check engine light would turn off its been six months since now the check engine light stays on and i have the same idle problem when i drive the car agressivly only i had the codes read it says its running lean in bank one and two i had a technician diagnose it and he said it was a leak in the rear of the lower intake manifold. so is that possible? is there any aftermarket lower intake manifolds? any help would be appreciated.

09-28-2009, 08:53 AM	#2
SuperG Registered User Join Date: Nov 2005 Location: Houston, TX Posts: 1,500	I wonder if you could also have a bad O2 sensor(s)...hopefully someone smart will chime in! __________________ Gary 1997 with Vortech V-2 SQ-trim 420 Hp/376 Tq at 5psi 2010 Shelby GT500 - Stock http://members.cardomain.com/supergr

09-28-2009, 08:56 AM	#3
nckissfan Everyone hates a winner! Join Date: Jan 2004 Location: Browns Summit, NC Posts: 2,810	I second the bad 02 sensor __________________

10-01-2009, 09:25 PM	#5
cobrabitn Dr Jekyll on the street, Mr Hyde on the track Join Date: Jun 2001 Location: Rock Hill SC Posts: 14,649	Well, that's possible but I would check other items first before I went into taking the intake off or apart. 1. Check the idle position sensor for proper setting 2. Check to see if the MAF sensor is clean and doesn't have dirt on it. 3. You don't really tell much about that car, is it stock or are there headers on there? Could you have a vacuum leak prior to the sensor in which it will make it seem like it has a lean condition when it doesn't? __________________ Cobrabitn 2016 Ruby Red Metallic with Caribou accent F-350 Crew Cab Stump Puller! 6.7 Diesel Automatic with Chrome Package, Off Road Package, 3.55 Locking axles, and Ultimate Lariat Interior Trim Package! 2017 Shelby GT350 Coupe - track car! Mods: JLT True Cold Air oil catch can 2009 Vista Blue Shelby GT 500 Coupe - Garage Queen Tinted Windows JLT True Cold Air Kit Pro-Dyno Tune 526 rwhp - 511 rwtq 1994 Rio Red Indy Pace Car #22 "Runabout" Snake in the grill MGW shift knob 1996 SVT Cobra Wheels 1969 New Lime Mustang Mach 1 Sportsroof - Second owner - bone stock with shaker. One SVT Cobra, one Shelby GT500, one 69 mach 1, and a Shelby GT350 is better than nothing! Custom Data Plates for your Mustang or Ford! Buy "Cool Merchandise" at Data Plates Plus www.dataplatesplus.com See my MSR Video here!

10-01-2009, 03:53 PM	#4
pvtdiaz Registered User Join Date: Sep 2009 Posts: 4	i changed the two front ones with brand new bosch ones and the two rear ones are denso's they look good

10-02-2009, 08:08 PM	#6
pvtdiaz Registered User Join Date: Sep 2009 Posts: 4	well i took the car to the ford dealer they finally found the problems it is a vacuum leak from the intake but also they told me i am going to need the imrc plates so i was wondering if i should delete or replace them with new ones and if anybody know any mechanics in the los angeles area

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