My car is lagging when I accelerate (almost leerching). It is fine once I am above 50 mph. I haven't changed my fuel filter in a while and was wondering if that is a symptoms of an old fuel filter.

 

Get MAF checked.

Get coil packs checked.

Do you have the CEL light on?

 

It came on, but went away (I just hit 120K and thought that it was a light that would come on for 60K mile service)

 

I need to change the spark plugs as well - could this have an effect?

 

how many miles on the present plugs ? replace with ngk platinum, is the knock sensor ok ? are you using premium fuel ? check codes, fix anything that needs to be tended too, then service your engine and go from there.

 

Do a tuneup since you need it and then come back here

 

get whatever codes that are stored in the ecu and then find out what they mean using the ecu fault code diagnosis. i found out i had 2 problems:
the line pressure solenoid valve due to the drop resistor mod and the knock sensor.

thought my car ran fine although it was kinda sluggish below 3000rpm but after i changed the KS, car pulled so much harder. i can peel out everytime from a stop now! WHOOO!