DOHC surging on accleration

timbo3282 · 08-29-2001, 03:37 PM

My 97' Cobra does not acclerate smoothly. When I am on the gas hard it seems like there are flat spots in the accleration where the car stops pulling. I have 45K on the car and my thoughts are:
1. The clutch is starting to slip.
2. The car needs the spark plugs and wires replaced.
3. I just replaced the fuel filter to make sure that wasn't the problem.

I bought Bosch Platinum Spark Plugs but may take them back and get the motorcraft double platinums, and I have the MSD 8.5 mm wires. Am I on the right track? Has anyone had a similar problem and resolved it? Any ideas?
Thanks.

95mustanggt · 08-30-2001, 01:42 PM

Check your TPS. If there are some damaged parts on the sensor resistor wire strip, it could cause you to flatten out on your acceleration. However it would do it whenever you get on it, regardless of RPM (it measures TB valve position). Check the sensor to and move it from idle to WOT and make sure that the voltage increase is nice and smooth.

Pull your plugs and have a look at them, check the gap too. I recommend just plain jane Motorsport plugs.

Maybe you could also give some more detail and it would be easier to home in on the problem.

------------------
1995 Mustang GT

timbo3282 · 08-31-2001, 10:50 AM

What other info would you like, the car is basically stock besides a Ram Air kit. The surging does happen every time I get on it, so I will check the TPS. I think I have ruled out the clutch, it does need replaced because it slips on power shifts, but I don't think it would slip and grab in a way that would give a surging feeling. I will also pull the plugs and give those a look.

King Snake · 08-31-2001, 11:47 AM

I have also had the surging problem. I noticed it after I changed the plugs, but I'm not sure if that was the problem. I installed NGK plugs instead of the Motorcraft Double platimun. The plugs that came in the car were different for each bank of cylinders. Four had a different part # from the other four, and looked a little different. I am considering purchasing some new Motorcraft plugs (the ones the book says to use) to see if that makes a difference. According to the manual, it says only use those factory plugs. Does anyone know why they are different?? I have noticed that over the past couple of months that my surging problem has gotten a little better, though.

------------------
'97 Cobra, Rio Red, MAC Cold Air Kit, 3.73s, NGK V-Power
BBK H-pipe w/cats

timbo3282 · 08-31-2001, 02:22 PM

Yeah the factory plugs have platinum electrodes on one bank and platinum conductors on the other. I think I am going to get the double platinum plugs from ford and put in my MSD wires and see if that helps the problem.

08-29-2001, 03:37 PM	#1
timbo3282 Registered Member Join Date: Aug 2001 Location: Itasca, IL USA Posts: 11	DOHC surging on accleration My 97' Cobra does not acclerate smoothly. When I am on the gas hard it seems like there are flat spots in the accleration where the car stops pulling. I have 45K on the car and my thoughts are: 1. The clutch is starting to slip. 2. The car needs the spark plugs and wires replaced. 3. I just replaced the fuel filter to make sure that wasn't the problem. I bought Bosch Platinum Spark Plugs but may take them back and get the motorcraft double platinums, and I have the MSD 8.5 mm wires. Am I on the right track? Has anyone had a similar problem and resolved it? Any ideas? Thanks.

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08-30-2001, 01:42 PM	#2
95mustanggt Registered Member Join Date: May 2000 Location: Kamloops, BC Posts: 2,875	Check your TPS. If there are some damaged parts on the sensor resistor wire strip, it could cause you to flatten out on your acceleration. However it would do it whenever you get on it, regardless of RPM (it measures TB valve position). Check the sensor to and move it from idle to WOT and make sure that the voltage increase is nice and smooth. Pull your plugs and have a look at them, check the gap too. I recommend just plain jane Motorsport plugs. Maybe you could also give some more detail and it would be easier to home in on the problem. ------------------ 1995 Mustang GT

08-31-2001, 10:50 AM	#3
timbo3282 Registered Member Join Date: Aug 2001 Location: Itasca, IL USA Posts: 11	What other info would you like, the car is basically stock besides a Ram Air kit. The surging does happen every time I get on it, so I will check the TPS. I think I have ruled out the clutch, it does need replaced because it slips on power shifts, but I don't think it would slip and grab in a way that would give a surging feeling. I will also pull the plugs and give those a look.

08-31-2001, 11:47 AM	#4
King Snake Registered Member Join Date: Jan 2000 Location: Warner Robins, GA, USA Posts: 210	I have also had the surging problem. I noticed it after I changed the plugs, but I'm not sure if that was the problem. I installed NGK plugs instead of the Motorcraft Double platimun. The plugs that came in the car were different for each bank of cylinders. Four had a different part # from the other four, and looked a little different. I am considering purchasing some new Motorcraft plugs (the ones the book says to use) to see if that makes a difference. According to the manual, it says only use those factory plugs. Does anyone know why they are different?? I have noticed that over the past couple of months that my surging problem has gotten a little better, though. ------------------ '97 Cobra, Rio Red, MAC Cold Air Kit, 3.73s, NGK V-Power BBK H-pipe w/cats

08-31-2001, 02:22 PM	#5
timbo3282 Registered Member Join Date: Aug 2001 Location: Itasca, IL USA Posts: 11	Yeah the factory plugs have platinum electrodes on one bank and platinum conductors on the other. I think I am going to get the double platinum plugs from ford and put in my MSD wires and see if that helps the problem.