Bad hesitation driving up hill under 2500 RPM - 2003-04 Mach 1 Registry Owners Club

Oxford White · 10-16-2010, 10:25 PM

Can anybody tell me why going uphill my all stock 03 Mach 1 has bad hesitation? If I jump on the pedal it goes away. Since I went up hill this one time the car now acts up on level roads. Its only accuring under 3000 RPM. I"ve heard the IAC MAF could be the probs. But uphill is what's weird that the power is lost. Its an automatic and if I get on it the RPM tops right before the red line @ about 5000 brakin the tires loose 40 MPH and also coming out of 2nd gear @ 5000 brakin the tires loose 60 MPH. Still has that, but slow rolling the streets @ 30 mph is getting worse. Thanks for any help.

mcruz7699 · 10-18-2010, 04:49 PM

My 04 Mach I is hesitating below 2K RPM but it's very slight. It also disappears above 2K on the Tac. I took the car to inspection and it failed emissions, OBDII showed "unsupported" across the board and should have read "ready". Had a mechanic run a diagnostic, found #5 cylinder ignition coil had low output under certain RPMs caused a misfire and a fuse to blow (cigarette lighter of all fuses). Replaced fuse, replaced the ignition coil (roughly $80 from Ford dealer), reset CPU, and drove 150 miles. Back to inspection this morning and still showing unsupported, another fail at the inspection station. I may end up at the Ford dealer to get this one fixed if I can't trouble shoot it. I'll let you know how it turns out.

Monster Mach · 10-18-2010, 06:49 PM

i had that problem replaced the coil in 5 and changed all my plugs.. symptom went away for a while now the plugs need a changing again

Oxford White · 10-18-2010, 08:22 PM

How often are you replacing the plugs Monster Mach? I'm only at 53,000 on my mileage.I'm trying to find an honest meechanic to look at my car so I can get it done the right way. I may end up at the dealership myself.Let me know how it goes.

XSELLR8 · 10-19-2010, 04:43 PM

I would almost guarantee it's the coil packs more than the plugs (the part that hooks onto the spark plug). I had one go out on my 01 GT...it did the same thing.

Monster Mach · 10-19-2010, 08:13 PM

Quote:

Originally Posted by Oxford White

How often are you replacing the plugs Monster Mach? I'm only at 53,000 on my mileage.I'm trying to find an honest meechanic to look at my car so I can get it done the right way. I may end up at the dealership myself.Let me know how it goes.

i change them every 20 or so... but thats a very very hard 20k

10-16-2010, 10:25 PM	#1
Oxford White Registered User Join Date: Oct 2010 Location: Dublin, Ca. Posts: 4	Bad hesitation driving up hill under 2500 RPM Can anybody tell me why going uphill my all stock 03 Mach 1 has bad hesitation? If I jump on the pedal it goes away. Since I went up hill this one time the car now acts up on level roads. Its only accuring under 3000 RPM. I"ve heard the IAC MAF could be the probs. But uphill is what's weird that the power is lost. Its an automatic and if I get on it the RPM tops right before the red line @ about 5000 brakin the tires loose 40 MPH and also coming out of 2nd gear @ 5000 brakin the tires loose 60 MPH. Still has that, but slow rolling the streets @ 30 mph is getting worse. Thanks for any help. Last edited by Oxford White; 10-16-2010 at 10:26 PM. Reason: incorrect spelling

10-18-2010, 04:49 PM	#2
mcruz7699 Registered User Join Date: Nov 2009 Location: Somerset, NJ Posts: 1	Re: Bad hesitation driving up hill under 2500 RPM My 04 Mach I is hesitating below 2K RPM but it's very slight. It also disappears above 2K on the Tac. I took the car to inspection and it failed emissions, OBDII showed "unsupported" across the board and should have read "ready". Had a mechanic run a diagnostic, found #5 cylinder ignition coil had low output under certain RPMs caused a misfire and a fuse to blow (cigarette lighter of all fuses). Replaced fuse, replaced the ignition coil (roughly $80 from Ford dealer), reset CPU, and drove 150 miles. Back to inspection this morning and still showing unsupported, another fail at the inspection station. I may end up at the Ford dealer to get this one fixed if I can't trouble shoot it. I'll let you know how it turns out. Last edited by mcruz7699; 10-19-2010 at 10:26 AM. Reason: spelling

10-18-2010, 06:49 PM	#3
Monster Mach Registered User Join Date: Oct 2009 Location: Endicott New York now maryland ft wash for work Posts: 1,123	Re: Bad hesitation driving up hill under 2500 RPM i had that problem replaced the coil in 5 and changed all my plugs.. symptom went away for a while now the plugs need a changing again __________________ 04 mach 1 Oxford white For h.i.d's dont buy ddm or hid guy.. buy vvme.com they are the best and by far the cheapest

10-18-2010, 08:22 PM	#4
Oxford White Registered User Join Date: Oct 2010 Location: Dublin, Ca. Posts: 4	Re: Bad hesitation driving up hill under 2500 RPM How often are you replacing the plugs Monster Mach? I'm only at 53,000 on my mileage.I'm trying to find an honest meechanic to look at my car so I can get it done the right way. I may end up at the dealership myself.Let me know how it goes.

10-19-2010, 04:43 PM	#5
XSELLR8 Mach-o-holic Join Date: May 2010 Location: La La Land Posts: 1,276	Re: Bad hesitation driving up hill under 2500 RPM I would almost guarantee it's the coil packs more than the plugs (the part that hooks onto the spark plug). I had one go out on my 01 GT...it did the same thing. __________________ 2003 Mach 1 TR 5 Speed IUP Bolt ons: You name it! 4.10s too 2004 Cobra Screaming Yellow 2.3L Whipple Gear install vid https://www.youtube.com/watch?v=tJrAIDCpbDI Clutch Replacement Vid http://www.youtube.com/watch?v=UFr0Rur_EWc Wideband Install Vid http://www.youtube.com/watch?v=GmL1KBmWyhg

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