Leaking Fuel Injector?? - Any Tips

[Jim Jermain]

I have a '00 XLS 4.0 OHV. I am trying to track down a very brief rough idle condition at start up. The car runs rough for only about 30 seconds. I've tried replacing the fuel filter, spark plugs, plug wires, upper intake manifold gasket, and injector o-rings. I haven't tackled the lower intake manifold gasket. I did get a misfire on cylinder 3 a few weeks back. When I replaced the fuel rail gasket and injector o-rings, I made sure the fuel rail studs and intake manifold bolts were tight. A few were a little loose. After I changed the fuel rail gasket and o-rings, the car ran great for one week. Now the rough idle is back.

Here is the strange part. If I hold my foot on the pedal a little when I start the car, it tends to car great and idle smooth. However if I don't touch the pedal, it will start and run real rough for the first 30 seconds or so. I haven't really noticed any loss of coolant and I have pulled the number 3 plug after letting the car sit over night to see if it smells of gas or coolant. No noticeable coating or smell.

I'm wondering if I have a leaking fuel injector or is it most likely a leaking lower intake manifold gasket. Any tips on checking for a leaking fuel injector? I was go to put a fuel gauge on and see if I lose pressure overnight. I'm just not sure if it is supposed to hold pressure all night. My manual says it should hold 30-65 lbs for five minutes. I never have the rough idle if I start the car again within a hour. It's only when it sits for several hours and is worse when it is colder.

I really appreciate any tips you might provide. I am stumped.

Thanks.

Jim

 

[2000StreetRod]

fuel injector cleaner

I usually add a bottle of fuel injector cleaner to my tank after replacing the fuel filter.

I suggest that you clean the IAC valve if you haven't already done so.

Some members have had problems with Bosch platinum plugs.

 

[Jim Jermain]

Thanks for the tips. I have tried cleaning the IAC. But I will try the injector cleaner and replacing the #3 plug. Certainly easier and cheaper than pulling the intake.

Jim