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View Full Version : 05 lgt studder problem plz help!!


scooby05lgt
06-13-2010, 10:45 PM
i was on my way home fron the local meet and on the interstate cruising at 70 mph my lgt started to hesitate or studder ever 2-3 seconds. i accelerated slightly(50% throttle in 5th gear) and acted fine. let off the throttle, same acted normal.. held the throttle to keep it at 70 and it studdered again. i did this with the ac on and off. i also tried the cruise control and got the same result.. doesanybody know whats wrong? fuel pump? ignition? any help would be great!

stock, open dp, k&n panel filter, and APv2 stage 1.. been running this for about 3 weeks and just started acting up tonight..
Robbks
06-14-2010, 10:19 PM
Given it's happening on constant (light) throttle, the o2 sensor in the exhaust is stuffed.
the o2 sensor tells the ECU how rich/ lean the exhaust gas is and the ECu compensates. a dead sensor will give incorrect readings and the car will usually run very rich (and poorly) at light throttle.
it's fine under hard acceleration as the o2 sensor is ignored by the ECU.

The other option is the Oiled K&N Filter could made the AFM (Air Flow Meter) dirty.
clean the AFM with electrical contact cleaner (no residue, No lubrication)
but i suspect the o2 sensor is the culprit.

other option could be the coolant temperature sensor. also adjusts fuel mixtures
and finally, it could be a boost/ vacuum leak, check all your intake hoses and vacuum lines for leaks/ cracks splits, loose, etc
98outbackpdx
08-29-2010, 01:40 AM
when was the last time you did your fuel filter? inexpensive fix it that is the issue.
kw521
08-29-2010, 12:30 PM
My car is doing the same thing as well....I read up and researched some things...could it also be boost oscillation?
Reuben
08-29-2010, 10:00 PM
o2 sensor is my guess too, and yep, AFM is second guess.
curse
10-06-2010, 10:31 PM
yeah i'm checkin in to see if anyone's pegged this one down yet or not. i've got a friend of mines car is doing it also. i replaced plugs in it last weekend and same thing. i'm going at it again this weekend checking fuel pressure and what not but if anyone had narrowed it down it'd be nice to know. thanks.