Ok, i'm having some trouble with my car and I need some ideas from people.

I have lost tons of gas mileage. I have no clue why, i just all of the sudden started to get worse gas mileage than i used to. I used to be able to get about 130 miles in a quarter of a tank when full. Now i can only get 80.
I seem to have lost power. It just all of the sudden doesn't seem as fast as it used to be. I have a cone intake (some crappy one from auto zone that costs 15 dollars) I did a type of short intake setup. I twisted the batter so now the filter is in front of the batter right behind the headlight. I have a Magnaflow muffler with 2.25 inch cat back piping (but with crappy pressure bends). When i punch it my intake sounds like it being restricted really badly. I am thinking i am loosing performance and gas mileage because i hear a really bad exhaust leak in the front somewhere (probably the dang studs which i know a pair are broken). Could a bad leak in the manifold be causing this? Please help. Thanks.

 

How about a knock sensor issue, could that be the problem? It could be retarding your timing at WOT and messing up your fuel economy.

 

no, can't be that. i have vg. i just recently changed my oil and put some slick 50 engine treatment in there and changed my plugs but not much changed. i did notice it ran a little smoother when i changed the plugs but still having the same trouble.

i think a motor/tranny mount may be bad. when i shift at low rpms from 1st 2nd the thing hops around like i'm driving at 700 rpm in 4th, whereas when i first got the car i could shift at 2000 rpm and it would just drive like normal.

 

Check the ignition timing, then the EGR valve. Push up on the diaphragm with the engine running. It should (a) move and (b) make the engine stumble/stall. Does it knock/ping at all. To check mounts, open hood, put e-brake on, and slip clutch in first and then reverse..see how much the engine moves. If it jumps all over, sounds like clutch chatter or broken mounts (one often casuse the other). You could also get out a big prybar and use it to move the engine. You'll be able to tell which is busted. By the way, I replaced my tranny mount (the one on the passenger side, kinda smallish) and it still sucks. Just a bad design. I even replaced all mounts, filling the gaps with liquid urethane from Mcmaster Carr, 80 durometer. Next move is to gut my used ones, establish proper sleeve location and fill 'em solid witht the 94 durometer stuff.

 

thanks for the info. i'll try the timing and egr stuff. i don't really know what pinging or detonation sounds like but i'm sure if i heard it i would be able to tell and i don't hear any abnormal sounds. i only run 92 or higher octane gas in my car so i know it won't ping from the type of gas. i have a crappy motor mount from my gxe (had a new one put in) so i'm going to try making a solid polyurethane mount with that. again, thakns for the info. i'll go try it real quick.

 

Exhaust leaks will really hurt gas mileage. When my stock y-pipe was leaking, I got about 260 miles off a tank. Now with a WSP Y, I regularly see 360 miles per tank!

 

sweet. that's it right there then. i'm hearing a bad exhaust leak (right after my muffler was put on too) so i'll do down there and ask them if they can find it. more than likely it's my broken studs though

 

I hate those damn studs. Make surre you use the turbo style ones when you replace them. In fact, when I ordered mine from Brown and Brown nissan in Tempe AZ, I forgot to specify that, but they sent them to me anyway. Just a heads up.

 

they a little stronger or something? what price did you pay for them? thanks!

 

I wish I got that good of milage...I get about 180 to a tank... and have no power.. ...and a going bad fast clutch...

 

It doesnt matter if you order the turbo studs or not since Nissan has upgraded all their new parts to stronger materials. So if you order regular exhaust studs for your car you'll get the upgraded studs.

 

Just going by some past info, plus the baggies they came in said turbo style, so I just assumed they were beefier.
LUV4DSC, sounds like you need some help dude! Fix the gas issue first..that's a drain on the wallet..tune that **tch up. Then take the money you would have been spending on gas and start fixin gthe other crap. Good Luck

 

so far egr is fine. i need to check timing now. i did find out my pcv valve wasn't hooked up correctly so now that is fixed. not sure if that will really do anything though. does anyone know what that piece is on the top right of the intake manifold (if you are looking at it from the front of the car) when you give the engine gas that thing is supposed to move, mine doesn't. will that do anything?

 

Not sure about what you mean. The only thing I can think of that moves with throttle is the linkage itself at the TB. PCV is always good to have working. It prevents gumming up of the crankcase and contrary to what many believe, it can and does increase the output of an engine. Some guys running dinosaur engines, pushrod eights and the like, hook up vaccuum pumps to the crankcase. Claims of 20-30 hp are not uncommon, but I can't remember why. i know it aids in sealing the rings and does something for oil control also..oh yeah, aids in drainback of oil in wet sump systems. I'm sure there's more to it, but at the least, a working PCV is important. Stuck closed and the crankcase pressurises killing your front and rear seals, oil pan seals and others and causing oil consumption up past rings. Stuck open and open and it will suck oil through the intake and burn oil that way.

 

umm yeah how old is that O2 sensor?

 

Good call. O2 is key

 

wouldn't the CEL turn on if it was O2? i can't believe i didn't notice it but what happened on the pcv this is the hose cam off of the intake so it was sucking in normal air and i have no clue what the hose from the valve cover was doing being unhooked like that. hopefully nothing got ruined though.

 

I wouldn't worry about damage. That was a major vac leak though! All better now though right! Keep in mind that was unmetered air going in so it may have been contributing to poor performance.

 

yeah i have the pvc stuff fixed now.

 

lazy borderline O2 = no light
dead O2 = light

you might have a lazy one.

 

wouldn't happenn to know how much runs would you? thanks for the info.

 

approx $110-$120 OEM

 

I use to get 11 to the gallon before the tune up. But now all that is left is the 02 which I got for $33 shipped and should have by weeks end. But Still don't know exactly where all my milage goes....but hopefully the 02 will fix it. I just need the y pipe.