Need help....

[DVrec21]

Whats up guys, I am posting about an issue I've been having for a few months now. I bought my 99 z28 stock with an LS1 6spd, only 113k miles on it. car runs great. Seems like ever since I put my ngk spark plugs in and slp long tube headers and y-pipe with cat deletes, the car has been running weird. When i give it throttle it holds back and has a lag. feels like a throttle lag. I have a stock ecu, with stock tune and thought maybe I just need a tune. I checked my engine codes, only codes I have are no cats, and a heater sensor which is bad. If I floor the pedal sometimes it takes a little biit like 2 seconds and then it just takes off like it should. Just wondering why I have this problem?? I thought maybe it was because I had a stock air filter with a full slp intake setup, but I recently put a K&N in and it still does it. Let me knooo if u have any suggestions thanks!!

[basballny2]

sounds like a possible fuel related problem or you just need a tune. check your fuel filter and if you havent replaced it recently do it anyway. i think my fuel filter was like 15 bucks

[DVrec21]

that is another thing that I have been thinking... do fuel filters go bad after 100k miles on our cars?? I'll buy one anyways. I remember while ago I when I was putting my headers in I accidently broke a sensor and drove the car around for a little that night. the car ran weird and the fuel pump was making a noise in the back. I replaced the sensor right after that and the car ran fine, just with this issue I have now. maybe the pump is going bad??

[KahanaReef]

At 100k if it hasn't been changed, it's time to change it. I think I read that it should be changed at either 50k or 75k. Not sure. I changed mine at 70k after I bought the car. The one that was on it was stock.

[Spaz]

a few things... if you put the headers in and got rid of the cats did you use 02 simulators in the rear 02's or have them tuned out??? the oil on the K&N filters is known to get on your maf sensors and throw off it's readings... fuel filters should be changed every 3rd oil change... they are cheap and easy to do... what part of PA are you from???

[KahanaReef]

fuel filters should be changed every 3rd oil change...

I've been doing it wrong

[basballny2]

i heard of fuel filters every 15k miles or so. but its a cheap start and cant hurt to do it. change it out and let us know how it goes. if i remember correctly the fuel filter is located about middle of the car on the drivers side.

[JayTA98]

Did you check the gap in your spark plug also before you put them in? I used NGK's and I had iddle issues badly. I tried settign the gap and couldn't get them to work right. I went back to the ac delco platinums. Not sure what my problem was but it was the spark plugs.

[DVrec21]

hmm... hopefully its just a fuel filter. I have never changed it since I had it and doubt that it has ever been changed. I bought the car with 107k on it, the abs module was bad, and I replaced that. the brakes I still have to do, will do them this weekend. I'll change the fuel filter then let u guys know how it goes. by the way I never notice it cut back once I'm fully on the throttle... just when I start going it holds back a little and if I give it full throttle it waits 2seconds then goes... which is what made me think it needed a tune but, seems like its strugglin for fuel I dont know...

[DVrec21]

a few things... if you put the headers in and got rid of the cats did you use 02 simulators in the rear 02's or have them tuned out??? the oil on the K&N filters is known to get on your maf sensors and throw off it's readings... fuel filters should be changed every 3rd oil change... they are cheap and easy to do... what part of PA are you from???

Yes I have O2 Simulators and no the cats werent tuned out. I'm in bristol PA like 15mins north of philly.

[35th-ANV-SS]

What are the actual codes that you pulled? The numbers on them?

[DVrec21]

What are the actual codes that you pulled? The numbers on them?

I'd have to goto my mans shop and check the codes again. I'll post them tomorrow because I have work all night

Edit: They were an O2 sensor code and a heater sensor. thats all I could remember but I'll hook the scanner up again tomorrow and write em down.

[DVrec21]

Never had the chance to pull the codes again. been busy with work. but I did however manage to do the fuel filter on sunday. wasn't that bad. Its hard to say but the car does seem to be running better since I did that. I heard that it is possible the intake manifold gasket is leaking a little bit. Any ideas on how I could check to see if it is leaking or not?? Any1 ever have this problem??

[az gt eater]

i just sawa thread on here recently where the guy had r and r'd his intake and then checked his intake bolts soon after and found one loose. You could remove it, and check the gaskets and reinstall it in a couple of hours. Wouldnt cost you a dime. Just pay attention when you remove the bolts, and you would know if anything was loose.

[ChvyCruzen]

the oil on the K&N filters is known to get on your maf sensors and throw off it's readings...

Sorry for the thread jack .. but you got me worried.. I just bought an 01 SS with 40k miles and the K&N filter on it was loaded with so much crap I'm surprised the motor could breathe! I had to clean it 3 times before it was acceptable and then re-oiled. I let it sit for about 3 hours before I drove it.

Suppose I got oil on the MAF. Will it eventually go away or ??

[JayTA98]

No it won't go away. You have to remove the MAF and clean it with MAF sensor cleaner spray.

[0rion]

clean the MAF ( can buy CRC MAF cleaner at any parts store) and get a tune. Another thing to check is that there are no wires laying on the headers that might've gotten burned.

[DVrec21]

hehehh... Well finally all my problems are solved!! Turns out it wasn't an intake manifold gasket leak, or bad fuel pump. Turns out I just needed a TUNE!!! I took my car to Race Proven in Delaware, had them check it out, told them my exact mods and the next day they dyno tuned my car. Turns out I was running so lean that when they first put it up on the dyno it only made 190whp! Yes to the wheels lol... after the 4th pull when tuning was done, they made 331whp with 347wtrq!! On a stock LS1...just bolt-ons and spark plugs!! They defffffff know a thing or 2 about tuning lol!! I reccomend Race Proven to anybody....

[35th-ANV-SS]

hehehh... Well finally all my problems are solved!! Turns out it wasn't an intake manifold gasket leak, or bad fuel pump. Turns out I just needed a TUNE!!! I took my car to Race Proven in Delaware, had them check it out, told them my exact mods and the next day they dyno tuned my car. Turns out I was running so lean that when they first put it up on the dyno it only made 190whp! Yes to the wheels lol... after the 4th pull when tuning was done, they made 331whp with 347wtrq!! On a stock LS1...just bolt-ons and spark plugs!! They defffffff know a thing or 2 about tuning lol!! I reccomend Race Proven to anybody....

What was your A/F?

[DVrec21]

my A/F read steady across at 13. at around 3.25 it dipped down a little bit I think the air flow not sure which is which. I can take a pic if u want to see.