1988 Mustang Gt Convertible seems like it should have more power than this

Discussion in 'Fox 5.0 Mustang Tech' started by Centaur, Jun 17, 2011.

  1. I bought a 1988 mustang gt convertible and it seems like it is putting out only 75 % of the torque. I remember gt's pulling me back in the seat when accelerated and mine just seems to fall short of the g force. When i spin tires from a take off, i can fully spin 1st then after shifting into 2nd my tires wont spin regardless of how high my rpms before the shift. I cannot even spin in first gear from a rolling start. Is this normal? I dont really care much about spin, but the torque pull i need!
    The motor seems to be running fine but it's like the power is not making it to the rear end. No smells no noises but also no torque. So i had my 3.08 pulled out and a 3.73 installed and was thinking this would solve it. It didnt. When i hit 3+ rpms the power fades even though the engine is behaving normal and sounding bad ass but its just lacking. Before i bought it, the car sat for a couple years and was loaded with mouse nests all over the place and chestnuts in the engine compartment! So im thinking maybe some sort of gnawing could have occurred? I have had a full tune up, but i dont think my fuel filter was replaced so i will replace it this weekend. Anyways im bummed because my ride is not up to her full potential. Any ideas would be greatly appreciated.
  2. Two quick, free and easy power gains:

    1: Remove the stock air silencer in the passenger's fender well.

    2: Check the timing and set it to 14* btdc. You can advance it even futher if you're willing to pony up for premium fuel.

    One other thing to bear in mind is that the 'vert is a couple of hundred pounds heavier than GT hatchback. That might have something to do with it.
  3. Any reason to think you have an exhaust restriction? Clogged cats from nest material, etc?
  4. Please describe the car's engine and transmission. Is it all stock? Auto or 5 speed?
  5. 1988 Mustang GT convertible,5 speed,3.73s,75mm bbk tb,76mm c+l mass air meter calibrated @24lbs,ford racing fuel injectors(24lb.),bbk fender wall mount cai,bbk shorties,summit racing H pipe(off road),bbk extensions,flowmaster 3 chamber muffs. I added the 373, the rest was already there when i bought the car.
  6. Ditch the C&L MAF and the 24 LB injectors and put the stock 19 Lb injectors with a 94-95 Mustang MAF. You don't need them on a stock engine, and the C&L MAF has a reputation for problems, especially with cold air kits.

    Once you have put everything back to stock or near stock, dump the computer codes.

    Dumping the computer diagnostic codes on 86-95 Mustangs

    Revised 3-Jun-2011. Removed the link to BATAuto.com and troublecodes.net instructions on codes and how to dump them. Post the codes you get and I will post 5.0 Mustang specific code definitions and fixes.

    Here's the way to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

    Be sure to turn off the A/C, and put the transmission in neutral when dumping the codes. Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.



    If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.


    The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

    89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.


    The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

    WARNING!!! There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.

    What to expect:
    You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems. This is crucial: the same wire that provides the ground to dump the codes provides signal ground for the TPS, EGR, ACT and Map/Baro sensors. If it fails, you will have poor performance, economy and driveablity problems

    Some codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

    Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.

    Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

    Alternate methods:
    For those who are intimidated by all the wires & connections, see Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

    Or for a nicer scanner see Equus - Digital Ford Code Reader (3145) – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.
    Or for a nicer scanner see http://www.midwayautosupply.com/p-7208-equus-digital-ford-code-reader-3145.aspx– It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.
  7. Tried cleaning maf sensor. no change. new fuel filter. no change. Checked the codes got an 11 so i rolled the dice and swapped out the old CnL maf for a new Pro-M designed for fender mount CAI and also replaced the throttlebody after trying unsuccessfully to clean it up 3x (was barely sticking open at times causing my rpms to rise in between gears and other times it just stuck shut).
    BIGTIME difference in torque and now i can light up rolling in first. Can chirp but still cant burn into 2nd. The torque in 2nd pulls me back into the seat now where before it was similar to the power of 2nd gear on my 10 speed bicycle.
    To Jrichker, the reason i didnt downsize to 19's is i plan on upgrading the engine and it would have cost me $ince the previous owner did all the mods, with exception to the 3.73s, and sold me the car without the old stock parts.
    So now i still have 24lb injectors/maf PLUS acceptable torque and i am looking forward to getting a trickflow top end kit new fuel pump and some sort of boost (probably a blower) this winter to accommodate the 24lb mods. I will have more questions for you before this happens. Thanks for all the sound advice J and the rest of the Stangnetters.:SNSign: