Hesitation in acceleration - could use some input.

[KAIN81]

2003 V8 LS - extremely well maintained and driven it's 90k by a woman in her 70's. Just got it about 3 months ago.

What i've done to it:
100% synthetic oil change
new air filter
Fuel Injection cleaner (only run 91)
switched to NGK Iridiums (coils looked fine)
Flowmaster 44's (kept resonators on)

The problem:
The car was hesitating when I accelerated in and around the end of 2nd gear - so I changed the plugs last weekend. It now idles better, and sounds cleaner - BUT I'm getting some very small but noticeable back fire and still can feel/hear the hesitation in and around 2nd gear.

The only thing I can think of, is maybe the fuel filter needs to be changed. I'm used to working on older cars with quite a few less variables - so any input would be appreciated.

Thanks in advance.
Here's the ride:

 

[jarrett88]

Not really sure if fuel filter will do anything, however I read somewhere that you need to do the fuel filter like every 15k miles, and due to the location I can see why.

 

[jmtiseo]

Going with the generic answer of replace the COPS (coils) and it won't hurt to replace the fuel filter, it's like a 10 minute job on these. A coil isn't going to look bad but the things are sensitive to those.

Welcome fellow LS owner!

 

[joegr]

Yep, replace the coils and make sure the plugs are correctly gap'd. (A tiny difference in gap can make a big difference in the way that it runs.)

 

[KAIN81]

Thanks all - I'll tackle the fuel filter today, didn't realize it was that easy to get too. Usually those are a pain the ass to reach. I'll look into it.
If that doesn't solve the problem, i'll look into the coil replacement.

 

[regiment1]

Thanks all - I'll tackle the fuel filter today, didn't realize it was that easy to get too. Usually those are a pain the ass to reach. I'll look into it.
If that doesn't solve the problem, i'll look into the coil replacement.

Apparently there is a fuel shutoff valve you can turn off, and let the car idle until it dies, so you don't get fuel spilling when you take off the filter.

 

[joegr]

Apparently there is a fuel shutoff valve you can turn off, and let the car idle until it dies, so you don't get fuel spilling when you take off the filter.

It's easier to pull the fuel pump fuse (#17 in the trunk for gen II), than to trip the impact fuel cutoff switch. This [pulling the fuse] is the factory procedure. Personally, I just throw a couple of paper towels over the connection to keep the gasoline from spraying anywhere. Even if you depressurize the fuel line, you're still going to spill gasoline out of the filter.

 

[KAIN81]

Wow - good to know on both counts guys. Thanks. Like I said i'm used to working on classic cars where getting doused in Gas is just part of the job - but if i can avoid it, I'm down. Thanks again.

I'll report back on if this cures the issue.

 

[KAIN81]

So I just pull the passenger side wheel and the splash guard and the filter should be right there?

 

[1LoudLS]

drivers side. cant miss it.

 

[joegr]

So I just pull the passenger side wheel and the splash guard and the filter should be right there?

Like he said, the driver's side (unless you have right hand drive). You'll need the Ford fuel line quick disconnect tools as well.

 

[KAIN81]

MF'r at the parts store told me passenger side. I totally would have taken off the wrong wheel. lofl. This is a saturday job - I'll let you know if it works. Thanks again.

 

[M4rk]

Since his is an 03, it's likely he will not need any tools to disconnect the filter. See my Fuel Filter Information thread for directions.

 

[joegr]

Since his is an 03, it's likely he will not need any tools to disconnect the filter. See my Fuel Filter Information thread for directions.

Quite true, but then it is an early 03 or a late 03?

 

[KAIN81]

Quite true, but then it is an early 03 or a late 03?

It's smack in the middle - June of 03 - guess I won't know if i need that tool until i get the wheel off.

 

[jarrett88]

Trust me if my dumb self can do a fuel filter anyone can

 

[KAIN81]

Mine had the dual green tabs as well - swapped out the filter in under 10 min. I could tell it wasn't the OE filter, but had still been there for far too long. I also took the time while i was there to pop out both sides to my inner fender, clean them and paint them black, cleaned my calipers and rear of my wheels, before putting it back together.

Regardless, to report back after two days back on the road - it fixed the issue. So mild hesitation in acceleration and audible back fire in 2-3rd gear can be the result of an old fuel filter. Thank god I don't have to replace the coils or take all of those new NGK's out!

Thanks for the helps guys.