car bucking

289 · 11-07-2003, 01:02 PM

my 89 gt is not running right at no load situations. I cruise down the highway and under 2k it really bucks Like it is missing then its alright then missing again. Almost like the timing or the fuel mixture is changing under the same conditions. I had this problem before but it went away when I changed plugs and wires and put 89+ octane in it. I started puttin 87 in and it got really bad all of the sudden. Also I does not idle well any more up and down almost stalls then it catches its self What should I look for Thanks

stang_racer20 · 11-07-2003, 01:07 PM

does it get worse when you step on the gas a little, then better when you let off the gas?

289 · 11-07-2003, 01:43 PM

No it tends to get better when I hit the gas and worse the more I let off. But what were you thinking I'm open to ideas

stanger9219 · 11-07-2003, 01:57 PM

my 92 has an extremely similar problem and i have yet to find what it is. Does yours start to backfire in the intake manifold? The list of things that i have changed is too long to say. Im told that th problem might be either the coil pick-up or a feul pump going bad.

289 · 11-07-2003, 02:49 PM

No mine does not backfire though the intake. It just jerks and hesitates

Coupe50h · 11-07-2003, 02:51 PM

sounds like a coil, or coil wire.

289 · 11-07-2003, 03:11 PM

Thats the weird thing the coil was replaced with an MSD coil

QuantumMotorsports · 11-07-2003, 03:11 PM

What's your timing set at? If it got worse when you put 87 in it, could be timing. Also could just be bad ignition parts. Could be coil, could be TFI module, could be the pickup coil in the distributor.

stang_racer20 · 11-08-2003, 12:18 AM

Quote:

Originally posted by 289
No it tends to get better when I hit the gas and worse the more I let off. But what were you thinking I'm open to ideas

well then i would say u-joints, but with what you say now its not, check your vacuum lines that would cause shuddering at idle.

Coupe50h · 11-08-2003, 12:38 AM

well i know i can feel my e-cam bucking my car a little, at a slow roll in gear......reason why i said coil wire, is cuz i had one go bad, but the wire was burnt inside the boot, and i didnt know until i pulled it off one day and it fell apart, i guess you could start on simple things, like check timing, cap and rotor ect... good luck

289 · 11-08-2003, 10:51 AM

Well here is what I found. I disconnected the idle controll valve and then the idle settled down so Its not a vacum leak. The rotor cap, wires, plugs, coil are all less then 5 months old. Where is the TFI located is that the ignition module. I also tried pulling the ignition timing conector( the little plug you pull to set the timing) so the timing would not change. And it got worst, the bucking that is. Now timing I had just recently moved my timing back when I began putting 87 in it. Question first what controls the Idle control valve and second how can I make sure my coil is well grounded to the block.
Thanks

Coupe50h · 11-08-2003, 11:24 AM

your coil should be fine, if it wasnt grounded, or was failing, it wouldnt start at all, they usually just go bad, not gradually.

I would clean the iac real good, and invest in a code scanner, they are like 30$ from autozone, it might give you an idea where to start.

11-07-2003, 01:02 PM	#1
289 Registered Member Join Date: Jan 2000 Location: Mount Joy, PA , U.S. Posts: 198	car bucking my 89 gt is not running right at no load situations. I cruise down the highway and under 2k it really bucks Like it is missing then its alright then missing again. Almost like the timing or the fuel mixture is changing under the same conditions. I had this problem before but it went away when I changed plugs and wires and put 89+ octane in it. I started puttin 87 in and it got really bad all of the sudden. Also I does not idle well any more up and down almost stalls then it catches its self What should I look for Thanks

11-07-2003, 01:07 PM	#2
stang_racer20 Registered Member Join Date: Jun 2003 Location: Wisconsin Posts: 348	does it get worse when you step on the gas a little, then better when you let off the gas? __________________ 92 Mustang GT, 347 Stroker(Forged Steel Crank/Rods-Balanced, Forged Aluminum Dished Pistons), Trick Flow Track Heat Intake, Trick Flow Twisted Wedge Heads w/ Stage 3 port/polish, 80mm C&L MAF, FMS 30# Inj., BBK AFPR, Trick Flow Stage 2 Cam, Trick Flow 1.6R Rockers, BBK E.L. Headers, Flowmaster Cat-Back, MAC CAI, FMS Pulleys, Griffin Alum. Radiator, MSD Pro-Billet Distributor; AOD, Dynamic 3300 Lockup Converter, B & M Super Cooler, B&M Ratchet Shifter; 3:73 gears.

11-07-2003, 01:57 PM	#4
stanger9219 Registered Member Join Date: Sep 2003 Location: st. louis, MO Posts: 197	my 92 has an extremely similar problem and i have yet to find what it is. Does yours start to backfire in the intake manifold? The list of things that i have changed is too long to say. Im told that th problem might be either the coil pick-up or a feul pump going bad. __________________ 98 Cobra, CAI, Flowmasters, o/r h-pipe. 4.10s, Hurst shifter.

11-07-2003, 02:51 PM	#6
Coupe50h Registered Member Join Date: Aug 2002 Location: SanAntonio, Tx Posts: 957	sounds like a coil, or coil wire. __________________ X-Texas highway patrol ssp 1990 coupe - exploder Gt-40 iron heads, Explorer intake, 19 lber's. E-cam. crane 1.7 rollers. 190fp. 75mm maf. 65mm tb, tubular subframe connectors, mac cai, Asp crank pulley, T-5, king cobra clutch, flowtech 1-5/8 unequals, mac X-pipe Frpp driveshaft, lakewood Lca's. race weight 3,160 12.69 @ 107.35, 1.71 60' 26x8.5 drag's 3.90 gear 13.20 @ 106.91 - 235/60/15 firestones 2.3 60' 3.27 gear

11-07-2003, 03:11 PM	#8
QuantumMotorsports Registered Member Join Date: Jul 2000 Location: Norman, Oklahoma, USA Posts: 597	What's your timing set at? If it got worse when you put 87 in it, could be timing. Also could just be bad ignition parts. Could be coil, could be TFI module, could be the pickup coil in the distributor. __________________ Michael Black QuantumMotorsports Norman, OK 1984 LX Hatch 306 w/ TRW forged flat toppers, Comp Cams Magnum 292H, GT40P heads w/ 3 angle valve job, .550 lift springs, Angus Racing Roller Rockers, Weiand Stealth Intake, Holley 4150 650cfm carb, MAC 1 5/8 Long Tubes, Single Chamber Flowmasters, 91' T5 w/ Pro 5.0 shifter, Turbo Coupe 8.8 Rear w/ 3.55 gears, QA1 Motorsports tubular K member, no interior except steering wheel and seat. Coming soon: 6 or 8 point cage, Fuel Cell, Weld Draglites

11-07-2003, 01:43 PM	#3
289 Registered Member Join Date: Jan 2000 Location: Mount Joy, PA , U.S. Posts: 198	No it tends to get better when I hit the gas and worse the more I let off. But what were you thinking I'm open to ideas

11-07-2003, 02:49 PM	#5
289 Registered Member Join Date: Jan 2000 Location: Mount Joy, PA , U.S. Posts: 198	No mine does not backfire though the intake. It just jerks and hesitates

11-08-2003, 12:38 AM	#10
Coupe50h Registered Member Join Date: Aug 2002 Location: SanAntonio, Tx Posts: 957	well i know i can feel my e-cam bucking my car a little, at a slow roll in gear......reason why i said coil wire, is cuz i had one go bad, but the wire was burnt inside the boot, and i didnt know until i pulled it off one day and it fell apart, i guess you could start on simple things, like check timing, cap and rotor ect... good luck __________________ X-Texas highway patrol ssp 1990 coupe - exploder Gt-40 iron heads, Explorer intake, 19 lber's. E-cam. crane 1.7 rollers. 190fp. 75mm maf. 65mm tb, tubular subframe connectors, mac cai, Asp crank pulley, T-5, king cobra clutch, flowtech 1-5/8 unequals, mac X-pipe Frpp driveshaft, lakewood Lca's. race weight 3,160 12.69 @ 107.35, 1.71 60' 26x8.5 drag's 3.90 gear 13.20 @ 106.91 - 235/60/15 firestones 2.3 60' 3.27 gear

11-08-2003, 10:51 AM	#11
289 Registered Member Join Date: Jan 2000 Location: Mount Joy, PA , U.S. Posts: 198	Well here is what I found. I disconnected the idle controll valve and then the idle settled down so Its not a vacum leak. The rotor cap, wires, plugs, coil are all less then 5 months old. Where is the TFI located is that the ignition module. I also tried pulling the ignition timing conector( the little plug you pull to set the timing) so the timing would not change. And it got worst, the bucking that is. Now timing I had just recently moved my timing back when I began putting 87 in it. Question first what controls the Idle control valve and second how can I make sure my coil is well grounded to the block. Thanks

11-08-2003, 11:24 AM	#12
Coupe50h Registered Member Join Date: Aug 2002 Location: SanAntonio, Tx Posts: 957	your coil should be fine, if it wasnt grounded, or was failing, it wouldnt start at all, they usually just go bad, not gradually. I would clean the iac real good, and invest in a code scanner, they are like 30$ from autozone, it might give you an idea where to start. __________________ X-Texas highway patrol ssp 1990 coupe - exploder Gt-40 iron heads, Explorer intake, 19 lber's. E-cam. crane 1.7 rollers. 190fp. 75mm maf. 65mm tb, tubular subframe connectors, mac cai, Asp crank pulley, T-5, king cobra clutch, flowtech 1-5/8 unequals, mac X-pipe Frpp driveshaft, lakewood Lca's. race weight 3,160 12.69 @ 107.35, 1.71 60' 26x8.5 drag's 3.90 gear 13.20 @ 106.91 - 235/60/15 firestones 2.3 60' 3.27 gear

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Bucking, bad Idle, codes 24,33,34	tomazzzo	Windsor Power	1	02-13-2004 12:03 AM
bucking & hessitation	stang4to8	Windsor Power	4	11-14-2002 08:39 AM
bucking In-tank fuel pump	mlambrecht82	Modular Madness	20	10-28-2002 12:56 PM
bucking & skipping	stang4to8	Windsor Power	8	10-16-2002 10:25 AM
What next? Also I have a bucking problem...	2FastLX	Windsor Power	2	04-28-2001 12:51 PM