99 Forester backfiring/no power

Friends 2.5 in his forester. It ticks like a bastard but its done that forever. Recently it has started holding back/misfiring/popping at around 3-3500 rpm. Sometimes he has to stop while driving because it does it so bad. If he holds it to the floor and lets it eat, then it sounds exactly like antilag. Have gone through multiple tanks of fuel so not junk gas. Changed fuel filter. Changed plugs and wires. Swapped a coil off my spare motor on. It does it hot, cold, after 30 seconds of driving or after 3 hours. All consistent. Any ideas? Ive never seen anything like it. Im thinking maybe his fuel pumps letting go? He gets all hot and bothered over compression so he checked that and its perfect. Told me he also changed his knock sensor?? Trying to help him figure this out. Clogged cat? The car burns oil like CRAZY. Thanks

-KB

Kind of sounds like it's in safe mode. Is it throwing any codes? Clogged cat?

clogged cat is our guess. With a quart a week of oil blowing through the cat, she cant be liking it......

Yeah no doubt lol.

if compression is so good, why is it burning so much dino juice?

got blue smoke from tailpipe?

Nigel Prodrive said:

if compression is so good, why is it burning so much dino juice?

got blue smoke from tailpipe?

Click to expand...

Yes. SO much smoke. When she sits for anything more then a day, it will smoke out like Seafoam. lol. Valves tick and clack like heck all the time. She still has full power up until the point in the rpm where it starts flattening and hesitating. Could it be valvetrain related?

-KB

if it's smokking, i doubt the compression is any good. something is wrong with the bottom end, or its getting back into the intake(pcv related). do a leakdown test

^ this  ^  

If there's a big puff of smoke on deceleration, that would indicate worn valve guides. If it smokes all the time, then it's rings -- or head gaskets if smoke is really white/gray steam, which means it's burning coolant.. have you been monitoring coolant levels thru all this? Look for signs of coolant and oil mixing (brownish sludge under oil filler cap, or milky-appearing oil on dipstick). Other signs of HG's going is oil in coolant (look for oily sheen in rad tank or overflow)

+1 for leakdown, done by someone who's experienced at doing them.

Yeah its oil for sure. Not coolant. Ill have him check what you mentioned. While intake was apart, he started it and I noticed how much air blows out of the crankcase vent... Think that's it? Choking itself out? Guess I should've been there we he did this compression test eh?

you need to do a leakdown test. you probably have a bad oil control ring, possibly compression rings too, which is causing the blow by and high oil consumption. without doing the leakdown, your guess is as good as ours

http://m.blackstone-labs.com/

Request an oil test kit and they can tell you exactly what's going on with your motor. It's only $28 and I got my kit within about 4-5 days

or do a leakdown test...

and find out way sooner

the thing that's irritating is that we are telling the op what to do to PROPERLY diagnose his issues, but he doesn't want to do that. I am about done offering any further help