sick stang - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

robert95 · 10-23-2003, 06:16

OK MongrelEB and anyone else,here goes.At cruising speed(4th or 5th gear) motor gets a hiccup or stutter like action.While accelerating or decelerating she runs great.Upgrades are as follows:Heads,upper and lower intake,MSD,Accel dist.,master blaster coil,Milodon hi-flo water pump,medium street cam,36 lb. injectors,new fuel rails.Might have missed a few.All upgrades were done 14 months before this problem surfaced.Have taken to shade tree and certified mechanics,can't find problem.The 89 notch 4 banger I just sold looks pretty good now!

At Wits End,
Rob

LunaticSVT · 10-23-2003, 09:41

have you looked at fuel lines, filter pump. I kno wyou say it is fine under acceleration and decel, but it is a thought.

have you checked the flow of the injectors?

I know it may seem silly and piddly little things, but it is those little things that can cause the problems. Besides what engine and year is this stang.

robert95 · 10-23-2003, 10:55

Fuel lines are flowing proper,filter is new.Have not checked inj.flow.Does it sound like a fuel issue? The motor is a worked 302,the skin of the car is 1995.Still dynos at past numbers before new problem.407 at rear wheels.

85GMarquis · 10-23-2003, 11:40

Sounds like fuel flow to me. When the Grand Marquis died on me it was fine till I got to cruising speed then it would lurch and buck then die. In my case it was a clogged fuel filter, if your filter is new then check the rest of the fuel system it is probably restricted somewhere along the line.

robert95 · 10-23-2003, 11:47

Would it show this problem under a load....like street racing.Not that I promote that.At the dragstrip or playing on streets she doesn't miss a beat.Only while cruising does it rear its ugly head.

'92BigBronco · 10-23-2003, 13:27

Check your EGR valve. I worked on a Toyota Celica (yeah yeah) with the same problem and went through the obvious. Checking fuel pressure and regulator, injectors, cap, rotor, plugs, etc. and after a lot of head scratching we decided to cap off the EGR between the intake manifold and EGR valve to see if that was the problem. Took it for a spin and the problem was gone. The EGR valve was the culprit.

mongrelEB · 10-23-2003, 15:59

Have you checked your TPS?
It does sound fuel-related, though.
What sort of ignition system is she using - dizzy, or coil packs? If coil packs, are there eight, or just four?
I had this same problem on mine what I installed the AU computer, turned out to be overfuelling. The waste spark was igniting unburnt fuel on the exhaust stroke and the motor was fighting against itself. If you have four coil packs, that might be your trouble....

robert95 · 10-24-2003, 06:41

Will be checking EGR this evening.Did you complete bypass the egr or replace it.To answer your question mongrel...a single Demon coil feeds the distributor.TPS???

mongrelEB · 10-24-2003, 15:44

Throttle Positioning Sensor.
If she's fuel-injected, she should have one of these on the throttle body. If that's buggered it can cause those problems.

'92BigBronco · 10-24-2003, 23:12

Yes, I replaced the EGR and all was well, but temporarily blocked it off to see if that was the problem. The symptoms you're describing are identical to the symptoms of the bad EGR. I will agree that a bad TPS will also cause the problems you're having. It's easy enough to test with a voltmeter.....

Good luck!