92 2.2 heavy bog help!

[urabus]

any help here would be greatly appreciated. have 92 leg 2.2 2wd auto . started intermittently bogging under load -now has condition all of the time. starts & idles fine .ok if throttle gradually applied. has no power & rpm's surge up & down 1-2000 rpm's if put under load in gear or of throttle snapped to WOT in park . has no CEL or codes . local shop replaced MAF when intermittent & was OK for 1 week -now does it all of the time .changed maf again -no change -said they pin checked all sensors- ok -suggested ECU -swapped with used one -no change. & plain gave up ! I changed camshaft sensor & knock sensor .pulled timing covers & checked marks -look like they line up ok .has recent coil ,wires,plugs,& reman injectors. before problem .changed fuel pump since problem-no change .sprayed intake, checked for vacuum leaks -all the basics -am I missing something here ? -havent had all that much time to throw at it, but now its critical (its my sons car!) anyone seen this problem before? -have 20+ years auto exp myself & have had plenty of subarus -never had this problem -has got me stumped!! please help! -posted on another so called subaru site but got crickets chirping for a response (snore) -theres got to be some subaru briainiacs out there!!! -thanks

[thehookeup]

check the IAC(idel air control) see if its bound up. also i would checck the power supply to the maf, and the return wire to the ecu from the maf. see if the voltage changes

[urabus]

checked IAC & MAF wiring -ok -anymore sugg?

[urabus]

I am starting to think its mechanical ( cracked or weak valve springs??? ) -anyone seen this ? engine did hyro-lock once several months ago when changing injectors -but was ok after plugs pulled to remove excess fuel -(has 170k on engine) -other sites say these engines suffer from sticky valves? (seems to be their diag for every strange running prob) -any takers? -I'll even post pictures of my 84 GL custom from '92 ( when I used to get lauged at for hopping up a Japanse car )for the die-hard who comes up with some answers (I think I hear the crickets again)

[Arctic Assassian]

do a leak down.

[urabus]

new development: checked IAC wiring per alldata -have 10 volts @#2 connector at IAC & correct voltage @ ECU connector (6&7 volts) -but have 0 ohms resistance at IAC itself (should have 9 ohms across terminals according to test plan) -should I condemn IAC? -would dead IAC cause my surge @WOT? with no CEL or codes? -seems to be a difficult /expensive part to just try dealers usually wont take these parts back once you try/open -any suggestions?

[thehookeup]

If you have a good junkyard available, thats a super cheap alternative. as long as your IAC has a signal i dont think it will throw a cel. Right guys? whats your location? (go to your profile and put your location in. it helps everyone out)

[urabus]

thanks -Is resistance test across terminals only way to check IAC itself ? - I see a few on EBAY $40-$60 -not too bad -just trying to limit the damage -already payed local shop $600.00 & they could not fix .

[thehookeup]

ouch.... well the valve inside the IAC can get gummed up and wont move or will move when it feels like it. but if you did the resistance test and your readings were zero then its bad. if you really wanna save money i would say you go to a junkyard. couldnt be more than ten bucks. and if you do the test at the junkyard you can make sure its not bad before you buy it.

[urabus]

thanks -junk yards arent that cheap here in NY (& they laugh when you ask for early 90's subaru parts) anyway-bought one off ebay -should be here this week I'll give it a try ...this ones really got me miffed -bought this car for my son because they are basically bulletproof-had a early production 90 myself & I guess it spoiled me -never so much as a hiccup in the 407,000 I put on (only didnt start twice -once due to bad battery 6years old! & once due to severly neglected spark plugs -150K on them-my bad) -car met its demise at the hands of a 16 yr old girl with daddy's pickup truck complete with trailler hitch backing into me full speed while stopped at traffic light (why to this day I still dont know?!?) -these are great cars -I guess my 18yr old could put a hurtin on just about any car -( think he's ruining my borrowed Durango as we speak) (smoked out 3 sets of brakes & 2 sets of tires on the subie in the year since he got it! -ugh! -teenagers!!!