yngmack923
New member
My Jeep has started to Stall on me at start up...I have to keep my foot on the Break & the Gas to get it moving...Recently I had a problem with a bad O2 sensor could this be the problem?
99 Grand Cherokee Stalling
- Thread starter yngmack923
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greg92jeepxj
Official Supporter
Although there are a list of preliminary checks such as fuel pressure and sparks quality and emmissions control system , knowing that you've already had a problem with a bad O2 sensor , it's likely the catalytic converter could be clogged and not allowing the engine to exhale.
A vacuum gauge can be used to determine if vacuum is lower than normal which would indicate poor intake volume due to poor exhaust exit as well as a lousy idle. Fuel pressure test is next.
A vacuum gauge can be used to determine if vacuum is lower than normal which would indicate poor intake volume due to poor exhaust exit as well as a lousy idle. Fuel pressure test is next.
Last edited:
Dragon5126
New member
since the 99 is obd compliant the first thing you should do id throw it on a reader and check for codes. Most parts stores will read codes for free but wont clear them. Not all codes trigger the engine light. As for the fuel pressure test, Greg92jeepxj is correct. HOWEVER, check for the location of your fuel filter. I'm not near my manuals at the moment and not sure of the location on your rig. If it's not in the tank, just go ahead and replace it as a matter of SOP. the fuel filter is one of the most neglected CHEAP service parts on a vehicle. At 14 years of age it is due for replacement, if it hasn't been done recently, anyway. and could save the pressure test at best, at worst, you would have performed a neglected service.
If it is in the tank and there isn't a service hatch in the floor, go right to the pressure test, but at the same time drain off some of the fuel into a clear GLASS Jar and let it set for a while and observe for any separation. A handful of years back my wife ran into this on her 95 GC after filling up put of town at an unknown station and ended up with water in the tank We fixed it by adding several gallons at a time of e-85 until it would idle (the alcohol mixed with the water making it burnable, just like HEET) and then topped it off with Premium (nonreformulated- no methanol) to reduce the alcohol ratio as much as possible and kept topping off every 1/8-1/4 tank for about 20 gallons
If it is in the tank and there isn't a service hatch in the floor, go right to the pressure test, but at the same time drain off some of the fuel into a clear GLASS Jar and let it set for a while and observe for any separation. A handful of years back my wife ran into this on her 95 GC after filling up put of town at an unknown station and ended up with water in the tank We fixed it by adding several gallons at a time of e-85 until it would idle (the alcohol mixed with the water making it burnable, just like HEET) and then topped it off with Premium (nonreformulated- no methanol) to reduce the alcohol ratio as much as possible and kept topping off every 1/8-1/4 tank for about 20 gallons
greg92jeepxj
Official Supporter
Thanks Dragon5126 , sorry I missed that , fuel filter. If my brother ever stays home long enough , like to crawl under his '99 GC to make sure if it has an in-line filter but guessing it does ?
Just hoping the injectors on yngmack923 's GC didn't get trashed like my brothers did. $$ :shock:
Just hoping the injectors on yngmack923 's GC didn't get trashed like my brothers did. $$ :shock:
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