car loses power up hills

[jameslibertygx95]

Hi there !
This is jameslibertygx95 and its awesome to be apart of the SUBARU LIBERTY CLUB

I recently bought a Liberty GX Wagon 1995 in very nice condition but much to my dismay it has a very weird problem of loosing power going up a long hill or after long periods of sustained acceleration. If i try to push through the power loss the car dies, but will start up straight away (sometimes after a short delay/depending on how hard i have pushed it) . I consulted a few mechanics and they thought it might be a faulty or dieing fuel filter or fuel pump, so i replaced them and this has made the car run better but has not changed the problem at all ;((( Does anyone have any idea what is wrong with my car ??? The only other suggestion i have heard is that maybe the holes where oil is suppose to be released in the hydraulic lifters are partially blocked and need to be cleaned out . My understanding is vague on what hydraulic lifters are but i understand what he means. My problem is that i am not filthy rich and it seems like i might need to have open heart surgery on my car !!!! If it must be done then so be it but does anyone have a better solution or does this sound like the problem ? Would putting a engine cleaner in my next oil change help loosen the blockage and maybe using a thinner oil say 10/30. The one FACT i know is that the previous owner used 20/50 oil which is thicker than the recommended oil for this model which is 15/40 & 10/30.

any suggestions ?
Thanks
jameslibertygx95

[subnub]

First off, welcome

I'm not a mechanic so take all of this with a grain of salt.

FYI, lifters (along with a couple of other bits) basically sit between the camshaft and the valve. When the cam turns and the lifter is forced up the lobe on the cam, the lifter transfers this force to the valve, making the valve open. Hydraulic lifters use oil pressure inside the lifter (which gets in/out via the holes you're referring to) in order to make the lifter expand to fill that cam/valve gap - effectively they can self-adjust, which makes them quieter and 'nicer' for a street car, and lower on maintenance as you don't need to shim them like a solid lifter. If your lifters aren't doing their job properly for whatever reason, the valves either won't open as much as they're meant to or won't close all the way, either of which could explain the loss of power. You can check both - if the valves aren't opening far enough I'd expect the lifters to be making a godawful noise, a loud ticking or clacking in time with engine revs. If they're not seating properly, the motor should be quiet and a compression check should come back low... the problem being that you say it only happens after hard use, so presumably the problem goes away too quickly to be able to compression test it.

Anyway, first thing I'd check is, how hot does it actually get? If things are getting waaaaay too hot the ECU might be putting it into a limp mode. If that's the case you'll need to find out why it's not cooling properly... blocked radiator, buggered thermostat, useless fan etc.

Failing that, in my limited experience when the car dies after hard use, it's often fuel related. You've done the pump and filter, so I'd be looking at anything that can affect the fuel pressure getting to the injectors. Vapourisation in the lines could be a culprit, which means that the fuel has started to evaporate in the fuel lines and can cause problems like you're describing, or maybe your fuel pressure reg is playing up and allowing too much fuel out of the rail. Or, going out on a limb, maybe the heat causes something in one of the pipes to expand which partially blocks the lines. You could try heat wrapping things to see if it helps.

You could try an oil additive, it might help if there is some kind of blockage. And a 20/50 is a little thicker than recommended but I wouldn't think it'd be think enough to cause any serious issues? I'd be a bit dubious about going too thin with the oil if your engine is the original one as well, things wear over time and thinner oil can get through smaller gaps. I'd stick with oils as the thicker end of the recommended range, the engine isn't a 9000rpm screamer anyway

[Adrian2627]

Try running some upper cylinder cleaner through it. If you've taken it to a mechanic I would expect they changed the plugs and check the coil pack. Being a 95 GX we are talking about a 2.0l SOHC engine right? If the plugs haven't been changed do that then the upper cylinder cleaner. It will smoke like a bastard for a bit but that's just the cleaner and all the crap being expelled. Have a search and you should find a DIY on where to put the upper cylinder cleaner into the manifold. The cleaner itself should be available from any Subaru dealership

[Ric]

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