What to do next ?

grey88gt · 06-26-2005, 10:45 PM

Bone stock 88GT AOD trans. What Ive done so far. New plugs, cap, rotor, wires, ignition coil, TFI module, 190 LPH fuel pump, ( yes its overkill for stocker) got a good deal on it, series 40 Flowmaster cat backs with turn downs at mufflers. Timeing is at 14, checked TPS voltage its ok. It has no vacuum leaks. Engine starts and idles fine hot or cold, runs great excellant power. My problem is at idle or under slight load ( say 1/4 throttle in any gear engine has a slight missfire. It does not backfire under any conditions. Step on the gas and it goes away. I have also put a fuel presure gauge on and with the vacuum line off its at 42 psi at idle 38 psi with it on. If I take the vac from the regulator at idle the engine stubles a bit but recovers with a slightly ruffer idle. Iam thinking that the injectors may be giving me the problem. I do have a new adjustable FPR not on yet. Whats left ?

Sry such a long post. Thanks In Advance

06-27-2005, 11:58 AM

While replacing your fuel pump, did you happen to change your fuel filter? That would be the first place I'd guess your misfire was coming from.

grey88gt · 06-27-2005, 09:31 PM

Sure did. Brand new Holly 190LPH pump kit with new sock and new fuel filter outside of fuel tank. It dosent act like its starving for fuel , in fact it runs great other than the slight missfire at times. Its got 2.73 gear and will bark sec. gear with no problem. Dosent run hot, like its to lean. I dont know, Iam going to put a spacer between the upper and lower intake, so ill just pull the injectors then and check them, and have them cleaned. Got a set of 3.55,s to go in soon to.

06-28-2005, 11:33 AM

What kind of spark plugs did you install? Every once in a while I hear a story on here of someone having similar misfire (or pinging) problems like you are experiencing. Some of those B.S. super duper spark plugs that companies are talking up these days have been the culprit of these misfire woes. Do you have platinum plugs in there? I've heard of the platinums freaking out the EEC-IV computer for some reason. Just something to think about...

grey88gt · 06-28-2005, 09:11 PM

Nope no fancy plugs. Put AutoLites back in. Regaurdless of what Ive done it hasnt changed or helped it in any way, other than the new Flowmasters. Seems as time goes buy its getting a little more present all the time, which leads me back to the injectors again. The car was only driven once a month for 4 years, until I got it. Only has 125,000 miles on it.

pearlgt40 306 · 07-04-2005, 11:46 AM

93 cobras came stock with platinum plugs. eec-IV should have no problem with that. fuel pressure is on the high side. also getting fuel injectors cleaned is not so cheap. near 100 dollars...and that wouldnt be worth it with 19lb injectors. there gonna hold you back in the future.. but as you know.. buying injectors means a mass air meter also.$$ and t-body. EEC-IV blows...no PIDS, no misfire detection. bullshit.

grey88gt · 07-08-2005, 09:17 PM

Yah I agree. I am getting the injectors cleaned for free. I sale alot of parts to a local truck shop and he said hed clean them for me for free. Iam not tryn to make a 10 sec car. Just something to cruise around in and have a little fun. I think I can get in the low 13,s pretty easy with out getting to crazy.

06-26-2005, 10:45 PM	#1
grey88gt Registered Member Join Date: Feb 2004 Location: Skiatook, Oklahoma Posts: 193	What to do next ? Bone stock 88GT AOD trans. What Ive done so far. New plugs, cap, rotor, wires, ignition coil, TFI module, 190 LPH fuel pump, ( yes its overkill for stocker) got a good deal on it, series 40 Flowmaster cat backs with turn downs at mufflers. Timeing is at 14, checked TPS voltage its ok. It has no vacuum leaks. Engine starts and idles fine hot or cold, runs great excellant power. My problem is at idle or under slight load ( say 1/4 throttle in any gear engine has a slight missfire. It does not backfire under any conditions. Step on the gas and it goes away. I have also put a fuel presure gauge on and with the vacuum line off its at 42 psi at idle 38 psi with it on. If I take the vac from the regulator at idle the engine stubles a bit but recovers with a slightly ruffer idle. Iam thinking that the injectors may be giving me the problem. I do have a new adjustable FPR not on yet. Whats left ? Sry such a long post. Thanks In Advance

06-27-2005, 11:58 AM	#2
Simi Stang Guest Posts: n/a	Re: What to do next ? While replacing your fuel pump, did you happen to change your fuel filter? That would be the first place I'd guess your misfire was coming from.

06-27-2005, 09:31 PM	#3
grey88gt Registered Member Join Date: Feb 2004 Location: Skiatook, Oklahoma Posts: 193	Re: What to do next ? Sure did. Brand new Holly 190LPH pump kit with new sock and new fuel filter outside of fuel tank. It dosent act like its starving for fuel , in fact it runs great other than the slight missfire at times. Its got 2.73 gear and will bark sec. gear with no problem. Dosent run hot, like its to lean. I dont know, Iam going to put a spacer between the upper and lower intake, so ill just pull the injectors then and check them, and have them cleaned. Got a set of 3.55,s to go in soon to.

06-28-2005, 11:33 AM	#4
Simi Stang Guest Posts: n/a	Re: What to do next ? What kind of spark plugs did you install? Every once in a while I hear a story on here of someone having similar misfire (or pinging) problems like you are experiencing. Some of those B.S. super duper spark plugs that companies are talking up these days have been the culprit of these misfire woes. Do you have platinum plugs in there? I've heard of the platinums freaking out the EEC-IV computer for some reason. Just something to think about...

06-28-2005, 09:11 PM	#5
grey88gt Registered Member Join Date: Feb 2004 Location: Skiatook, Oklahoma Posts: 193	Re: What to do next ? Nope no fancy plugs. Put AutoLites back in. Regaurdless of what Ive done it hasnt changed or helped it in any way, other than the new Flowmasters. Seems as time goes buy its getting a little more present all the time, which leads me back to the injectors again. The car was only driven once a month for 4 years, until I got it. Only has 125,000 miles on it.

07-04-2005, 11:46 AM	#6
pearlgt40 306 Registered Member Join Date: May 2002 Location: Long Island, NY Posts: 14	Re: What to do next ? 93 cobras came stock with platinum plugs. eec-IV should have no problem with that. fuel pressure is on the high side. also getting fuel injectors cleaned is not so cheap. near 100 dollars...and that wouldnt be worth it with 19lb injectors. there gonna hold you back in the future.. but as you know.. buying injectors means a mass air meter also.$$ and t-body. EEC-IV blows...no PIDS, no misfire detection. bullshit. __________________ 306 Short Block, Forged Pistons, GT-40 Irons, Ford Racing 1.6 Ratio Rockers, GT-40 Upper and Lower Intake, B-303 Cam, 24 lb Injectors, 70 MM Throttle Body, 75 mm MAF, MAC Cold Air Intake(in fender), March Ram Air Scoop, MAC Longtubes, Offroad H-Pipe 2.5", No Cats, 40 Series Flows, 2.73's(eek...), Kenny Brown Subframes, World Class T-5, Pro 5-0 Tower Shifter

07-08-2005, 09:17 PM	#7
grey88gt Registered Member Join Date: Feb 2004 Location: Skiatook, Oklahoma Posts: 193	Re: What to do next ? Yah I agree. I am getting the injectors cleaned for free. I sale alot of parts to a local truck shop and he said hed clean them for me for free. Iam not tryn to make a 10 sec car. Just something to cruise around in and have a little fun. I think I can get in the low 13,s pretty easy with out getting to crazy.