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car jerks when in gear at low rpm's?
my car runs great and idles perfect but when i have the car in gear (anygear)at low rpm's like when im coming to a stop it jerks as if u were in first and not giving it enough gas please help
------------------ 89lx cocaine white,cobra wing/emblems,chrome 18in cobra r's/nitto xtremes, gt40 longblock from ccm,forged pistons,f303,1.6 rockers,performer rpm intake,70mm tb,75mm bullet,bbk fenderwell induction,24#inj,190l pump,bbk fuel pressure regulator,140amp alt,msd ignition/disributor,aluminum 3 row radiator,bbk shorty's,off road h pipe,flowmasters,king cobra clutch,world class t-5,3.73's,strut tower brace,subframe connectors |
Sounds like your clutch is glazed. Try going to an empty, open parking lot, and just flat out dump the clutch several times. This will usually break the glaze.
Take care ~Chris ------------------ Retired Moderator MustangNet My site: JimPorterRacing RACECAR spelled backwards is RACECAR HEY !!! Are you ASE Certified ??? If you are, ask me about iATN. The best tool you'll ever have, and it's free !!! |
How low is low Rpms?
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Lumpy cam maybe, mine w/stock convertor does this, but that is soon to be fixed http://www.mustangworks.com/msgboard/redface.gif .
------------------ 89 Notch: ASP Pullies, K&N Air,Transgo shiftkit,Trans. cooler,FMS 3 core , FMS 4:10's, 1.5" cowl, cold air kit, hooker shorties(jet hot coated), O/R H-Pipe, ASP solid mounts, Energy Sus. Trans. Mnt. BBK 70mm TB, MSD 6al, Dual elec. fans, 5.0 Firepower Kit, Scorpion 1.6 RR's, Flowmasters, 73 mm MAF, cobra intake(ported), 1" phenolic spacer,ported stock heads and crower #512 cam. [This message has been edited by John (edited 09-29-2001).] |
when you come to a red light and u downshift to slow down it starts to do it or i can even be in 5th at 60 mph and if i dont steadily give it gas it will do it, i would love to dump the clutch but engine only has 250 miles on it and i dont want to uck anyting upthanx for the response!!!!!!!!!!!
------------------ 89lx cocaine white,cobra wing/emblems,chrome 18in cobra r's/nitto xtremes, gt40 longblock from ccm,forged pistons,f303,1.6 rockers,performer rpm intake,70mm tb,75mm bullet,bbk fenderwell induction,24#inj,190l pump,bbk fuel pressure regulator,140amp alt,msd ignition/disributor,aluminum 3 row radiator,bbk shorty's,off road h pipe,flowmasters,king cobra clutch,world class t-5,3.73's,strut tower brace,subframe connectors |
New engine huh. It never did this before the new engine? Is the clutch the same as before the new engine? Have you checked your vacuum?
------------------ Gunning for 12's! http://www.indianastangers.com/2Fast..._brd_logo2.gif Buy your parts here ICQ# 42269241 |
yeah its a new engine, it never did this before, everything is brand new from the radiator to the tranny, no vacum leaks either i dont think everything is hooked up or capped off, i think it might be my rear end i had the gears put in about 2 years ago and i noticed today there was some play where the driveshaft hits the rear end, could that be it?
------------------ 89lx cocaine white,cobra wing/emblems,chrome 18in cobra r's/nitto xtremes, gt40 longblock from ccm,forged pistons,f303,1.6 rockers,performer rpm intake,70mm tb,75mm bullet,bbk fenderwell induction,24#inj,190l pump,bbk fuel pressure regulator,140amp alt,msd ignition/disributor,aluminum 3 row radiator,bbk shorty's,off road h pipe,flowmasters,king cobra clutch,world class t-5,3.73's,strut tower brace,subframe connectors |
Do you have cruise control and does it work? It sounds like your speed sensor isn't working. If it's not that (cruise control works), it may be your idle air bypass valve.
I'd run the KOEO (quick test) and KOER (Engine running) tests to verify that all the sensors are hooked up properly and that the ECM can control RPMs via the idle air bypass valve. When things are operating normally the ECM will see that you are moving based on feedback by the speed sensor. If the ECM knows you're moving and your foot is off the accelerator it will open the IAB valve to keep RPMs up so it won't stall. One easy way to test this is to put the car in first and then accelerate until you hit about 1500 rpms (don't do this on a hill), hold that speed for a few seconds, and then take your foot off the accelerator. The ECM should be able to keep you rolling along without the engine stalling. If it surges a lot, it may just be a combination of a lumpy cam and the big throttle body. If it just stalls, I would guess that you don't have a working IAB valve or solenoid. Pulling your codes will probably give you the best answer. ------------------ 351W 89 Mustang GT Convertible |
lumpy cam? does that mean a new cam ****** i hope not im dead *** broke i have sunk 6 grand in my car in the last year i cant do much more
------------------ 89lx cocaine white,cobra wing/emblems,chrome 18in cobra r's/nitto xtremes, gt40 longblock from ccm,forged pistons,f303,1.6 rockers,performer rpm intake,70mm tb,75mm bullet,bbk fenderwell induction,24#inj,190l pump,bbk fuel pressure regulator,140amp alt,msd ignition/disributor,aluminum 3 row radiator,bbk shorty's,off road h pipe,flowmasters,king cobra clutch,world class t-5,3.73's,strut tower brace,subframe connectors |
How much vacuum is it pulling? My car would accelerate fine, roast the tires off, etc. It ran great at the higher RPM's and idled fine, but if you were driving below 1600RPM it would jerk, buck, and hesitate BAD! It turned out to be a vacuum leak.
How does the car run if you are cruising at a steady speed in the lower RPM range? Does it feel like you have to race the engine to keep it from surging? Now that mine is fixed it will drive at 35mph in 5th gear with no bucking at all (not that I drive it that slow in 5th). It may just be a bad IAB as Jim stated, but I'd eliminate evey easy fix you could before buying any expensive parts. ------------------ Gunning for 12's! http://www.indianastangers.com/2Fast..._brd_logo2.gif Buy your parts here ICQ# 42269241 |
I didn't mean that your cam was broken, I just meant that it was radical enough to cause a rough, or lumpy, idle.
Did you do that test that I described? ------------------ 351W 89 Mustang GT Convertible |
yeah my cruise control works and the car will not shut off it just bucks like a bull, as long as im giving it gas its fine i can be going 40 in 5th and it runs smooth, only when i let off the gas at low rpm's in gear does it do this it idles and accelerates great it has about 350 miles now and has plenty of power i stomped a 87-90 5.0 mustang yesterday with no problem we raced from second to third and i didnt even hit 5000 rpm's and his *** was toast, im very happy with the power it just has some small problems to be workd out but thanx very much for all your responses they are very much appreciated, cant wait to get 1000 miles on the car so i can stomp my friends 99 ls1 camaro at least i hope so lol thanx guys
------------------ 89lx cocaine white,cobra wing/emblems,chrome 18in cobra r's/nitto xtremes, gt40 longblock from ccm,forged pistons,f303,1.6 rockers,performer rpm intake,70mm tb,75mm bullet,bbk fenderwell induction,24#inj,190l pump,bbk fuel pressure regulator,140amp alt,msd ignition/disributor,aluminum 3 row radiator,bbk shorty's,off road h pipe,flowmasters,king cobra clutch,world class t-5,3.73's,strut tower brace,subframe connectors |
Mine did the same. after buying new O2 sensors and a New MAF sensor.. I had to just drive the car for several hundred miles and the ECM will LEARN and adjust itself to work out the BUCKS thats what mine did I have a BIG CAMshaft anI cruise 35 in 5th gear now easily and even as low as 20mph turnin in places...
------------------ SOLD THE 87GT, .. GT40, 70mmTB, 75mmBullet, 24lbinjectors, cold air induction, Edelbrok 6025 Rpm's, Inch phonolic spacer, tall FMSvalve covers, an SFI balancer, Canton 7quart, the shortblock... Lunati 51025 (224/232 .535/. 544 @112 deg) Ross lightweight pistons (10:1) Eagle H-Beams, Total Seal plasma Moly Rings, Clevite bearings, ARP throughout, FMS main Girdle&Studs, Forged Crank, of course HV-OilPump and hardened FMS shaft, Dual Friction centerforce, T5, and 4.10's Longtubes and 2.25 tail pi |
My car has the EXACT same problem. Its had it since the motor was put together w/ the heads,cam,intake. I hve tried everything to figure it out. It almost feels like a loose drivetrain, so I checked all that stuff, put in a new driveshaft, motor mounts, and transmount etc.
If you EVER Figure it out, PLEASE LET ME KNoW! About 2200 rpm or so it runs fine right? Skyler ------------------ -1989 Saleen Mustang #406- TFS TW Heads, E-303, Edelbrock intake, 70mm TB, 73mm MAF, 24lb injectors, 1 5/8 shorties, Off Road H, 3 Chamber flows, Jaz Race seats, Back seat removed, sub-frames, Roll Cage, and a 80 shot of N20. 12.54@107.4 Motor 332RWHP, 350rwtq |
yeah sky thats right man this really sux, also i love your combo i have watched your videos and thats one hell of a mustang, i just want to say that i have had my car for 7 years, i got it when i was a junior in high school and after rebuilding the engine once and the tranny twice i decided to go ahead and go for the gusto, if i had any brains i would of sold it a long time ago but i have had soo many memories in that car i cant bring myself to sell it plus the fox body mustangs are the best looking cars on the road!!!!!!!!!!!!! edelbrock heads and 150 shot coming in about a year WATCH OUT LS1's!!!!!!!!!!!!!!!!!!!!!!!!!
------------------ 89lx cocaine white,cobra wing/emblems,chrome 18in cobra r's/nitto xtremes, gt40 longblock from ccm,forged pistons,f303,1.6 rockers,performer rpm intake,70mm tb,75mm bullet,bbk fenderwell induction,24#inj,190l pump,bbk fuel pressure regulator,140amp alt,msd ignition/disributor,aluminum 3 row radiator,bbk shorty's,off road h pipe,flowmasters,king cobra clutch,world class t-5,3.73's,strut tower brace,subframe connectors |
mine does it to. right about the same rpms.
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hey sky or anyone else with the same problem do you have a chip? several mechanics told me thats the way it goes with a big cam and a stock computer, they told me to get a custom chip and that would work out the problem and if that didnt then it was a drivetrain problem
------------------ 89lx cocaine white,cobra wing/emblems,chrome 18in cobra r's/nitto xtremes, gt40 longblock from ccm,forged pistons,f303,1.6 rockers,performer rpm intake,70mm tb,75mm bullet,bbk fenderwell induction,24#inj,190l pump,bbk fuel pressure regulator,140amp alt,msd ignition/disributor,aluminum 3 row radiator,bbk shorty's,off road h pipe,flowmasters,king cobra clutch,world class t-5,3.73's,strut tower brace,subframe connectors |
Ok my car does this to and I fix it by turning up my fuel
pressure 5 psi. When i go to the track I turn it down agian because my car runs higher trap speeds when its leaner but the drivability goes away. Try it its free and wont hurt anything. Good luck ------------------ 93 coupe,373's ripper shifter,MAC 1-5/8 equal lengths,MAC 2-1/2" H-pipe with cats,flowmaster 2 chambers,lowered 1-1/2" with BBK springs.Motorsport HD clutch,,FMS pullies,75mm bullet maf,walbro 190 lph fuel pump,kirban adj fpr.edelbrock 6037's e303, cobra intake frpp 1.6 roller rockers mac cold air kit msd 6al 3" cowl hood factory five upper and lower control arms wms subframe connecter and strut tower brace 12.81@ 105.1 1.66 60ft |
fuel pressure is at 40 but ill try it thanx
------------------ 89lx cocaine white,cobra wing/emblems,chrome 18in cobra r's/nitto xtremes, gt40 longblock from ccm,forged pistons,f303,1.6 rockers,performer rpm intake,70mm tb,75mm bullet,bbk fenderwell induction,24#inj,190l pump,bbk fuel pressure regulator,140amp alt,msd ignition/disributor,aluminum 3 row radiator,bbk shorty's,off road h pipe,flowmasters,king cobra clutch,world class t-5,3.73's,strut tower brace,subframe connectors |
Have you pulled your codes yet? Done the Key On Engine Off quick test and Key On Engine Running test?
------------------ 351W 89 Mustang GT Convertible |
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