Chrismikeb

iTrader: (2)

Thats the best way i can describe it, doesnt matter what gear when i floor it i get a jerky feeling that i can feel and hear every 1k rpm or so...i think it occurs more in lower gears actually and i can hear popping once in a while, car is a 02 z28 6speed it has 1 3/4in headers to a 3in collector to 2.5in y wiht high flo cats, to a 3in slp loudmouth (dont know why the ypipe is 2.5in) i do have a SLIGHT exhaust leak near that v-band clamp on the driver side that holds the collector to the y-pipe thanks to speed bumps, and i noticed that the bottom of the headers on both sides are dented pretty good from hitting **** (car is lowered) i can get pics of it if that would help


could a combination of these 2 problems be the culprit? i had a major exhaust leak on my 93 and it only sputtered a little up until 2-2.5k...but the headers werent bashed in, Would appreciate any help

wssix99

iTrader: (5)

Sounds like a classic dirty MAF. Try getting some MAF cleaner for it and toss your K&N or oiled filter. The oil sheds off it and fouls the MAF.

Chrismikeb

iTrader: (2)

hmm worth a shot, i replaced the filter with a paper one when i got it, but under the hood is pretty dirty kinda looks like someone was mowing the lawn with the hood open...

wssix99

iTrader: (5)

The MAF has a heating element on it, which bakes off contamination. It can't deal with air filter oil, though, so you may have built up more contamination over time. When that happens, the PCM can't tell how much air is coming in to the engine and it will lean you out.

Chrismikeb

iTrader: (2)

the one i took out was paper also, not sure if there was ever a k&n in it...i was driving today in traffic and i noticed when id keep a steady speed i could feel it bucking and sputtering and crap, so its not just at WOT

wssix99

iTrader: (5)

gotcha. Cleaning the MAF is cheap and doesn't hurt. Regardless, it sounds like you either have an air or fuel problem.

- check air filter
- clean MAF

then....

- fuel filter
- check fuel pressure
- check fuel pump
etc.

Nate02Z28

I just spend nearly $70 on a K&N filter because my old paper one looked like crap.
I noticed it did seem a little oily when I put it in. My car now idles slightly lower, which was odd. But the temps are a little lower as well.

You really think K&N filters are that bad for the MAF?

bongva

iTrader: (7)

i agree, clean the maf, then maybe change the plugs?

Chrismikeb

iTrader: (2)

ya ill give that a try, sure it doesnt have anything to do with the exhaust like i was sayin? i mean its not terrible still pulls like hell but it is noticable

wssix99

iTrader: (5)

Of course, K&N doesen't agree that their filters do this. They say the MAF design is defective and GM has a TSB that says the filters should not be used.

In the end, the K&N requires more maintenance. For some people it's worth it others, not.

wssix99

iTrader: (5)

It could be a lot of things. If your pipes are really bad, it would give you an effect like someone putting a banana up your tailpipe. Mght be nice to post pics. Have your cats taken the same hits? They are fragile and have ceamic elements that can break and clog things up.

Did all of this start right after you hit a bump?

Chrismikeb

iTrader: (2)

well ive had the car about a month and i had high flow cats put on it, they look ok the speed bumps are plastic but freakin huge but i did notice that exhaust leak after going over them, and the headers were already dented in. i dont think this happened all of a sudden but ive never went WOT before since its my daily and i try to take it easy on it

Jays_SSZ28

iTrader: (2)

I just had a problem like this, my car would start misfiring at higher rpm accelerating. It would misfire and shake rarely driving normal or at idle also.
I cleaned the MAF, it was dirty, didn't help.
Changed the sparkplugs, that fixed the problem.

wssix99

iTrader: (5)

Maybe you are going too slow over the speed bumps? I suggest hitting them at over 50 mph so you go airborne and ramp right over them. I've never done it myself, but have seen it on TV.

Chrismikeb

iTrader: (2)

lmao well if it wasnt for the lake (pond) right on the other side i might be able to...

Chrismikeb

iTrader: (2)

i dont quite follow, u saying it rarely drove normal? or it would misfire and shake sometimes

Jays_SSZ28

iTrader: (2)

It would misfire around the same rpm every time I got on it hard.
Sometimes it would misfire then stop misfiring while driving normally.
Sometimes it would misfire then stop misfiring while at idle.

Chrismikeb

iTrader: (2)

oh ok...mines not that bad, yet. if nothing else works then it wouldnt hurt to change plugs.

also just a refrence to how much of a bastard these speed bumps are, it was raining today, i was goin slow over the speed bumps as usual and the clamp got caught on the speed bump and my 275mm wide tires were spinning trying to get over it..

Chrismikeb

iTrader: (2)

I really dont have a whole lot of time to screw with this but this morning i popped the hood and was late to work as it was so i briefly checked all the plug wires pushing on the ones i could get to, and i hear #1 click onto the coil pack also didnt see any burn spots on the wires but again i didnt have much time...i also been reading when guys tune their AIR out and change the crank position sensor the problem goes away...

so i took the fuse for the AIR pump out but it didnt really seem to help the situation, once the car warmed up it started sputterin when i got on it...But when it was cold it pulled pretty damn good didnt sputter a whole lot i think the exhaust leak has somethiing to do with it..

i also noticed the cap on my schrader (think thats how u spell it) valve is gone, but i dont think that would make this much a difference, and if there was fuel coming out of it pretty sure my car would be on fire by now (knock on wood!) what u guys think? im probaly gunna ask a delarship what they think when i go get inspected but i dont want them to **** on my cupcake and tell me its frosting