Driveability Issues

Discussion in '96-04 - 2V Specific' started by midnightper4mance, Apr 4, 2016.

  1. midnightper4mance

    midnightper4mance New Member

    Messages:
    3
    Likes Received:
    0
    Joined:
    Apr 1, 2016
    Hey guys, I need your help.
    I have a 97 GT 2v.
    I am having issues with my car running.
    It has a longer start. 7-8 cranks. sometimes it starts up good and idles good, other times it starts and dies no matter what i do. When it does start it idles awesome. now when i rev it up it sounds likes its missing. In park/neutral it used to be ok but now it is missing also. It used to do it just in gear under load. As far as mods go; i have a cold air intake, a 75mm throttle body, a plenum, and tb spacer. Nothing else is done to the motor other than I have a Bama (sct) Tuner that i have also been trying to mess with. But i need it running better first. I bought the car a few years ago and i registered it for the first year but then i repainted it. so it has been down a while. My first thought was bad gas. So i sucked out everything i could and replaced it with new. I replaced the fuel filter. No change. I checked plugs and wires. Looked good, didnt change them, looked new. I will change them soon anyway. But ive seen cars run on a lot worse. I know its not worth the fight, so i plan on changing them. But i am pretty sure that is not my issue. So i brought home my scanner from work and hooked up to it. and I had lean codes. So i go in and check trims. Sure enough my LFTRIMs were stuck at +25 at Idle. So I get out my brake cleaner and check for vacuum leaks, everywhere. Around the hoses in the intake, around the silicone couplers in the intake, tb gasket, plenum gasket, spacer gasket, all the pcv lines, all the vacuum lines, around the intake, in the injector ports, etc. everywhere. My fuel trims never change. At idle they are stuck at +25. as soon as i Blip the throttle the LFTRIM drops to +2 - 8. So it got me thinking. My MAF readings are ~OK~. at idle it reads 4-6g/s, and when I open the throttle it does raise but it starts stumbling so i cant get an accurate reading. but when i can get it to idle up it seems to read ok. cant do a wot pull but 2-2500 rpm it reads 14-17g/s. Like I said not 100 % accurate, but they read ok. I can sometimes get it to rev up if I ease into it. Slowly increase the throttle, it will rev to about 3000rpm then start stumbling. anyway as far as I can tell it is a stock MAF housing. I pulled the MAF out and looked at it and it looks brand new, nothing on the sensor. So I am wondering if I need to get a bigger MAF housing? The Injectors are stockers. I heard that you only need to upgrade the MAF if you upgrade the injectors? Correct? I tried unplugging the MAF and it seemed to run better. It will rev higher but still stumbles.
    It ran good the first year i bought it. but I got the itch and needed to modify. It had the CAI on it when i purchased it. But I put the TB, Plenum, Spacer, and tuner on. It is a SCT tuner I got from american muscle. Its a BAMA tuner. You tell them what you have modified and they write the tune for you and you just install it. So ive tried all of the different tunes wondering if one of them worked better. Nothing, I even returned it to stock tune, nothing still runs crappy.

    anyway I hope someone will read this and have some input. I really dont want to just start throwing parts at it. if someone has had similar experience or can give me something else to test that will be awesome. I will be bring home my Fuel Pressure tester tomorrow.

    Thanks in advance
    Jesse
     
  2. 03DSGGT

    03DSGGT SN95 Supporting Member

    Messages:
    723
    Likes Received:
    15
    Joined:
    Mar 10, 2011
    Location:
    Akron, Ohio
    Have you checked for intake leaks? The plastic intakes will crack and sometimes will leak coolant down into the spark plug wells. My buddies 96 had a similar issue that got worse and we found that the nipple on the rear of the intake was cracked and leaking coolant into the spark plug well. It may be worth a shot to pull your spark plug boots and see if you find coolant in any of the wells...
     
  3. midnightper4mance

    midnightper4mance New Member

    Messages:
    3
    Likes Received:
    0
    Joined:
    Apr 1, 2016
    Hey thanks. I have pulled all the plug wires and plugs. I see no sign of a leak. anywhere.
     
  4. 95GT86SS

    95GT86SS New Member

    Messages:
    86
    Likes Received:
    0
    Joined:
    Mar 18, 2016
    What's TPS voltage?

    Sent from my SAMSUNG-SM-G870A using Tapatalk
     
  5. 07GtS197

    07GtS197 Well-Known Member

    Messages:
    1,390
    Likes Received:
    186
    Joined:
    Mar 16, 2015
    Location:
    Naples, Fl
    It sounds like your maf is the problem. Clean it before moving forward and spending more money. Maf problems are common on 2v's but its usually just dirty not damaged so I think you should be ok after cleaning it.
     
  6. 96blak54

    96blak54 Legend

    Messages:
    7,449
    Likes Received:
    761
    Joined:
    Feb 21, 2011
    Location:
    Ky
    If the car ran 100x's better when you unplugged the maf....yea! The maf reading is faulty. Like 07GtS197 stated, dirt could be the culprit. Also the stock maf is perfect for any n/a power. If you feel the sensor is good, have it checked to be sure. Also check wiring, corrosion, breaks in the wires and such.
     
  7. JerZeyStangz

    JerZeyStangz Well-Known Member

    Messages:
    3,614
    Likes Received:
    39
    Joined:
    Jan 13, 2006
    Location:
    Northern NJ
    Another possibility that if you have the stock oem fuel pump, it could be on its way out. Majority of the time hard starts are from a weak fuel pump or battery. Just go through all the basic checks but my suspicion is on a worn/tired fuel pump.
     
  8. midnightper4mance

    midnightper4mance New Member

    Messages:
    3
    Likes Received:
    0
    Joined:
    Apr 1, 2016
    UPDATE.....
    Thanks everybody. I brought home my pressure tester. and sure enough i was only getting 18-20 psi. and it bled off quickly. bad fuel pump. Just installed a aeromotive 340 lph 90 psi pump. Runs good. Next up bigger injectors and maf to support. thanks again
     
  9. Thomas_W

    Thomas_W Well-Known Member

    Messages:
    1,478
    Likes Received:
    44
    Joined:
    Jan 25, 2007
    Location:
    Capon Bridge, WV
    Bigger injectors and a larger MAF arent needed, if you just have boltons, the stock stuff is plenty
     
  10. 96blak54

    96blak54 Legend

    Messages:
    7,449
    Likes Received:
    761
    Joined:
    Feb 21, 2011
    Location:
    Ky
    ^ yup. Do yourself a favor.....leave them alone
     
  11. lwarrior1016

    lwarrior1016 Moderator Staff SN95 Supporter

    Messages:
    5,631
    Likes Received:
    650
    Joined:
    Sep 22, 2014
    Location:
    South Mississippi
    MORE FUEL= MORE POWER!!!

    BIGGER AIR=MORE POWER!!!


    What could go wrong here?............