Please help troubleshoot my problem.

[Mock One]

slight miss at part throttle

47,000 miles is right about the time I needed new spark plugs. Don't ask why they didn't last 100,000 miles. I had the exact same symptoms. I suspected a bad COP, but they all checked out okay. Dealer replaced the plugs and I was cured.

 

[DGC GT 1]

I have the same problem and cant figure it out either. Mine only happens at about 1000 RPM's. I just started shifting a little higher so that my RPM's go above 1000. Other than that my car runs great with 65K, so im not too worried about it.

 

[blueconv00GT]

OK..I finally tackled this problem...you can see in my earlier post under this topic all that I have done to try and fix the problem. Today I went to pep boys and bought a replacement coil over plug and went thorough all of the coils one by one and drove the car in between each change to see if that coil was bad. Finally, I found the problem--second coil from the front on the passenger's side. my car runs perfectly now! i'm so excited to be able to drive around again without the constant hesitation...good luck fixing this problem on your car--i would definitely recommend troubleshooting the coils

 

[Mike97gt]

any chance you have had any engine work done. a camshaft pos. sensor installed wrong will cause problems like this. the amount of things that can cause a problem like this is endless. you may want too try what the other guy did and buy one coil and go around and install it on a cylinder and drive it until you eliminate all the coils. we have better tests at work but that requires the use of scan tools.


i would start with the coils if no engine work has been done . if engine work has been done look at the camshaft pos. sensor

 

[Dark Knight GT]

HELL NO Do not clean the TB with spray. It has a special coating on it and you will f'k it up...

What special coating would that be ? I ported and polished my stock throttle body to a mirror finish and cleaned it up with carb and choke cleaner. I've never had any problems with it either.

 

[YtnGT]

Could it just be drivetrain slop???

I have the same basic issues and I am positive that it's drivetrain slop. It has progressively gotten worse since about 20K now I'm at 45K+. It really does not bother me very much.

BTW my engine definatly does not idle as well as it did with stock platinum plugs. I am using two step cooler copper plugs now.

Just stop driving your mustangs like a grandma and you wont have these problems. J/K

 

[Dark Knight GT]

Could it just be drivetrain slop???

I have the same basic issues and I am positive that it's drivetrain slop. It has progressively gotten worse since about 20K now I'm at 45K+. It really does not bother me very much.

BTW my engine definatly does not idle as well as it did with stock platinum plugs. I am using two step cooler copper plugs now.

Just stop driving your mustangs like a grandma and you wont have these problems. J/K

I'm running two steps colder plugs as well, but I don't have any idle issues and my car runs fine. They've been in the car for close to a year now. I agree, stop driving the car like a grandma and everything will be ok lol.

 

[blueconv00GT]

so as u can see above my car was fixed sat afternoon in time to cruise around town...not more than an hour after I fixed the hesitation problem I was merging onto the highway ragging out my car pretty bad when my coolant light came on and i started to smell radiator fluid burning...my intake manifold has finally bitten the dust. so i limped it home and spent sunday installing a new intake manifold...that was fun. i really appreciate my mustang's timing though--I fix one thing and another immediately breaks.oh well, i like working on my car

 

[Dark Knight GT]

so as u can see above my car was fixed sat afternoon in time to cruise around town...not more than an hour after I fixed the hesitation problem I was merging onto the highway ragging out my car pretty bad when my coolant light came on and i started to smell radiator fluid burning...my intake manifold has finally bitten the dust. so i limped it home and spent sunday installing a new intake manifold...that was fun. i really appreciate my mustang's timing though--I fix one thing and another immediately breaks.oh well, i like working on my car

Sorry to hear about your bad break with the intake and coolant leak. At least you know how to work on your own car and you can fix things for yourself. Beats having to pay someone else to do it. Glad to hear you got everything fixed though. On a side note, I wouldn't blame it "all" on the Mustang though. Crap happens and parts break on ANY vehicle with time. Key to success with a vehicle is taking good care of it and when something breaks or goes bad, fix it.

 

[tanion]

Since I started this post I feel I should give an update as to what solved my problem. Tuning was apparently the culprit. As i mentioned earlier, this all started happening at some point after I had removed the Hypertech tuning and went back to the stock tuning over a year ago. Well to test my hypothesis that this actually was the problem, I put the Hypertech tuning back on a couple days ago. So far I haven't had the pulsing/jolting I was experiencing before and I've been trying to make it happen. The car is running much much better now. I think that the Hypertech unit screwed up the stock tuning program when I loaded back on to the car over a year ago. So I guess I'm married to the Hypertech tuning for now unless I get the ECU reflashed at the dealer or use some other tuning device.

 

[fourwindsoh]

After tune, bucking at a specific throttle position under load

Since I started this post I feel I should give an update as to what solved my problem. Tuning was apparently the culprit. As i mentioned earlier, this all started happening at some point after I had removed the Hypertech tuning and went back to the stock tuning over a year ago. Well to test my hypothesis that this actually was the problem, I put the Hypertech tuning back on a couple days ago. So far I haven't had the pulsing/jolting I was experiencing before and I've been trying to make it happen. The car is running much much better now. I think that the Hypertech unit screwed up the stock tuning program when I loaded back on to the car over a year ago. So I guess I'm married to the Hypertech tuning for now unless I get the ECU reflashed at the dealer or use some other tuning device.

Thanks for the details on the resolution.

I just got a custom tune after having LT headers, a catted X-pipe and plenum put on (with 3.73 gears, also). I am having a 'bucking/hesitation' problem at about 1/3 throttle. It always happens at exactly the same throttle position and always under load. If I quickly move the throttle from about 1/4 to about 3/4, the problem does not occur. The problem does not occur in neutral.

I'm taking it back to the shop to see if they can tweak the tune. Right now, it's what I'd like to call the 'whiplash' tune.

However, the car sounds great and feels great. I had 87 octane in my tank when I brought it to the shop and should have had 93 for the tune. I really wonder wether they should have tuned the thing with 87 octane. I was told that there was tons of detonation during the tune. I'm no expert, though. I was told to run 93 octane.
- Andy