Car Is Jerking..... Help

soupnutz said:

Is it only with slight throttle inputs, what if you go wot?

Click to expand...

PDOGG74 said:

I had the same problem as you and was told to go from the least expense to the most expense procedure when trying to fix the problem. It would jerk and hesitate but never throw a check engine light. I changed out the fuel filter first, I am glad I changed it, it looked like the original fuel filter and had black sludge looking stuff coming out the end that connects from the tank side. I cleaned out my air filter (K&N drop in filter) and still no change. I even changed out the spark plugs and checked the wires, still no change. I did some more research and found out for a 2003 MACH1 the COPs should be changed out around 90,000 or 100,000 miles. The current mileage on my car at that time was 135,000 miles. Had my mechanic friend look at my COPs and told me they look like the original that came with the car. I Sucked it up and changed out the COPs with Motorcraft COPs from EBAY. OMG big difference not only was my car miss-firing and jerking but didn't realize how sluggish the performance was ( this is my FIRST Ford Mustang and really had no base line on performance) before I changed out the COPs. It felt like I had a new tune in my engine and all I did was change the COPs. Before I couldn't go up a hill at 60mph in 5th gear without major hesitation and jerking during the rpm climb from WOT position. After the change I could be at 40 mph in 5th gear going up the hill in WOT and no bog, jerking or hesitation only steady smooth rpm climb. Let me know if my situation helps or you already changed everything out I mentioned above and still have the same results.

Click to expand...