[thisoldtruck2]

hello again, previously posted about my problem with a hesitation under light throttle around 1800-2000 rpm in my 98 auto, all stock, i believe i have found the culprit just not sure what the cure is, after close inspection and cleaning of everything imaginable and replacing my front o2 sensor, i remember being told that the egr opens at around the rpm condition exists. so i pulled the line off egr and plugged it and hesitation gone, so the question remains, why? well i'll tell you what i know, i vacuum tested it and it opens and closes,also opens when you twist throttle, i cleaned the whole inside where it closes and seats, i did notice that in my service manual there is a reference that it should open about 1/8 inch, mine seems to open more than that more like a 1/4 inch, which would kinda explain the hesitation cause it's dropping too much vacuum and leaning the mixture out and sucking too much exhaust in, right? so is it opening too far and if so any ideas why, i see there is some kind of vacuum modulator"looks like a flying saucer" with two vac lines in, one out to egr vacuum purge valve and another line that runs down to manifold next to egr. could it be faulty? any way to test it, or could return spring in egr valve weakened?i would be perfectly happy leaving it unplugged but it is kicking a egr code with line unhooked, thanks, and thank you to all who responded to my previous posts,

 

[TC2000]

I cant help you but ill bump it up, for interesting problem

 

[thisoldtruck2]

false alarm , still hesitating with egr unplugged, gonna try disableing awd, maybe it's some kind of torque bind, running out of ideas, got a real good local troublshooter who should be able to tell whats going on at time of hesitation, might be well worth the 75 bucks, can't believe both of my subarus have done this, have owned dozens of cars and never had this kind of drivability problem with a fuel injected vehicle, losing my love for the soobies, imo computer should either be compensating or throwing a code here, very annoying

 

[Woody '04]

i had a 93 chevy suburban (non obdII computer) acting up. after i tried inpsecting and examining many things i decided egr was most likely the issue and replaced it even though i couldn't find anything actually wrong. drove great after that.

i'm on my first subaru with egr. i don't think either of the 2000s I had before had this, at least not in the same location as my current 2004 that is very noticeable.

 

[thisoldtruck2]

i had replaced upstream o2 sensor a few days ago and today at least it seemed to behave itself, maybe old one couldn't adjust itself quick enough?gonna try a ecu reset and drive a couple days and see what happens, new egr is close to 200 bucks so gonna wait and see what happens. also saw that knock sensor connection has been rigged. male and female spade connectors in place of factory hookup, one crimp looks corroded and is hanging on by a few strands, just moving it around a bit set off a knock sens code, so gonna try to redo connection, can't hurt, this car has alot of issues, kinda dissapointed, thought with lower mileage116k would run like new, has two bad front cv joints, got the new axles yet to install, and rumbles around tight corners, not sure if axle related or a center diff studder, various creaks and rattles and a terrible wind noise from doors near mirrors, and a vibration in gear at idle.well they say not to buy a car that was a first year model. maybe they got better with time, wish i had my 183k legacy back it drove much better

 

[Woody '04]

pretty typical for front axles to go between 100-120 kmi. passenger side usually goes first due to being right over cat. but the axles aren't terribly expensive either for DIY.

if somebody messed up the knock sensor connector, they could've messed w/ other stuff too? :icon_frown:

the front window gussets can be very carefully squeezed together with large pliers and the underlying metal brought closer together to eliminate the worst of the wind noise. this has to be done very carefully or the rubber can be torn or separated from the underlying metal. this has worked well for me on a couple of foresters.

my favorite years for Foresters are 2000 and 2004, but there are always issues. :icon_wink:

 

[thisoldtruck2]

well went ahead and just replaced knock sensor, car seems much better, cruising around town seems to take less throttle, still not sure if hesitation gone but definately moving in a positive direction, still amazes me that these little sensors cost more than a new axle, thanks for the tip on the wind noise i'll give it a go, gonna be working on the axles this afternoon, have had the outer portion apart b4 to do a wheel bearing, the only uncharted territory will be driving the pin out that holds the inner to output shaft, it's funny the pass side has play and looks newer than drivers, maybe a cheap rebuilt, drivers inner boot ripped so gonna just replace unit, for 75 bucks an axle why bother with a boot , :icon_wink: