View Full Version : Bad miss on acceleration

11-26-2002, 11:13 PM
My 94 SC auto continues to give me fits. My SC fun meter is pegged! I have replaced every engine sensor, the computer, Ignition Control Module, plugs, Magnacore wires, no cats, magnaflow with turbos, etc. Just repaired three burnt wires in the primary power junction box (under the hood). I detected them because the wire side of the fuse case was burnt on three fuses: headlights (60 AMP), heater blower (60 AMP) and I don't remember the other 40 AMP fuse. Before I detected the burnt wire problem, I bought a real good code reader and for the first time in 8 weeks since owning this peice of SC crap, I have no fault codes. However, I have the same problem NO POWER AND TONS OF BOOST. I thought maybe the wire problem was affecting my electrical system voltage, thus affecting PCM sensor input. Well after I fixed the burnt wires I still have NO POWER AND TONS OF BOOST but now with a new twist. I have big time misfires when I accelerate. If I'm running say 60 MPH and kick in 10 LBS of boost it starts to misfire bad. When I let off the boost the misfires disappear. A bad coil you say well I replaced it and that is not the problem. I compared the 94's timing advance to my 90 Super Cougar. The Cougar advances and the SC does not. I'm convinced it is a timing problem. I replaced every component that would affect ignition timimg. Still get the same thing. I'm getting 11 MPG with the SC. My Cougar runs VERY STRONG and the SC barely runs. Any help or suggestions would be appreciated.

One other thing. The 94 SC has a Ford installed security and remote start system. The system operates fine. Has anyone had or heard of others having performance problems after these Ford systems are installed ?

Ed Springer

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90 Black Super Cougar 5-Speed, B&M Ripper, 94 blower with 5% pulley (what a kick ~~~ upgrade!) , 70MM TB, Headers, underdrive pulleys, no cats with Magnaflow, Magnacores, I/C fan, SCP Fresh Air Inlet, 3:27 gears, Air Bags, 94 Stock MAF.

94 Red SC Auto, Magnacores, 70MM TB, no cats with Magnaflow & turbos, SCP Fresh Air Inlet, 3:73 gears.

Aaron Pedroza
11-27-2002, 12:12 PM
Is it happening all the time when you get into boost or is it when it is cold? hot? Do you see the tach jump when it is missing? Are you sure it is when you get into boost or could it be rpm when it starts missing? These things could nail the problem down a little more.

11-27-2002, 12:53 PM
I too am experiencing upon acceleration a bad jerking and missing (sounds almost like pre-detonating), but last sat. I took SC to a mechanic who works on Ferrari's, Lambo's, Porsches, - he listened to it - then rummaged around in his parts bin and came up with a 'USED' MAF sensor that screws onto the MAF Meter - he exchanged it with my old sensor then we took it for a test - this smoothed out the acceleration tremendously but not COMPLETELY - he told me to go BUY the correct sensor as this one was calibrated for 24# injectors and my stock injectors are 30# I believe. I am now looking for a new sensor aftermarket or complete intake including sensor and meter and tube w/KN filt., as opposed to buying OEM sensor from Ford for $300.plus which only comes with Meter assy.
Hope this may help your prob!

Thomas A
11-28-2002, 12:23 AM
You might want to try cleaning your MAF sensor wires...or....

Crazy Thought: You say tons of boost, but no power. And also no timing advance. Could you be running lean and encuring detonation, thus causing the knock sensor to pull timing? Bad detotnation(Dale P's car) can feel like it is missing. Just a thought?


David Neibert
11-28-2002, 01:23 AM
Sounds like it's starved for fuel. Check fuel pressure on the rail, it should be about 40 psi with vacuum line off and increase pound for pound with any boost. For example 10 pounds of boost should show 50 pounds of fuel pressure.

If pressure is low, it is either the fuel pump, pressure regulator or fuel filter.