where are the cliff notes? i don't think its your fuel pump cause when mine went bad the car would jerk if i tried to give it gas more than 30% throttle. if you had a fuel pressure guage you could just look at your fuel pressure but i don't think thats going to help you....hmmm BUMP maybe someone else will put there 2 cents in. I'll still think about it too :thumbup:

 

so did you fix your problem? if yes how did you fix it.

 

thank you.

 

i got an update for you guys,after observing my car for the longest time i took it to the guy that did my swap and i explained to him the symptoms,he said it sound like the o2 sensor so we did a little test he unplugged the connection of the o2 sensor and the car idled perfect,but the CEL is on which is normal he said coz we took out o2 sensor, he told me to drive it for couple days and see if it would still sputter and jerk,it idled better but still sputtered and jerks but not as bad as before, so it made us believe it's the o2 sensor,so he changed it at the same time i ask him to change my cat to a hi flow cat coz maybe that's what causing the problem too, he put a 2 1/4 magnaflow hi flow cat.after everything was installed car runs fine at that day,and then today i drove my car on the highway then i noticed that my car sputters and jerks around 4000-5000 rpm randomly and it idles low around 300-600 rpm but sometimes it idles fine then drop again, but even it idles low the motor seems to run finr it doesn't shake or vibrate that it's gonna stall.the car runs good when accelerating and i noticed one more thing if i step on the gas usually 3rd and 4th gear just holding it steady around 2500.2700 rpm the car will jerk a little bit like it bogs or something.this is what iv'e done,
1.spark plugs
2.spark plug wires
3.cap and rotor
4.fuel filter and fuel injection flush 2x (always runs fine for few days after flushing the injectors)and pulse test for the fuel injectors with good results.
5.ignition coil brand new
6.got the ignition timing checked
7.iacv cleaned
8.o2 sensor brand new
9.magnaflow hi flow cat
do you guys have anymore ideas what's up? please reply thanks.

 

fuel pump, or fuel pump relay

 

but the mechanic said if it's the main relar or the fuel pump the car won't start at all, is this true? or the car will still start up right away eventhough i have a bad main relay and fuel pump? thanks.

 

maybe you start to loose fuel pressure at some point of driving, then it comes back.

 

I still don't find what is my problem with my car. The problem in my car seems when the temperature outside is hot and the load is heavy (uphill for example).But it happen also when downhill and then do complete stop. Does it possible the problem occur cause the position of the car (for example on down/uphill)? One thing I know it make the problem less is before I have MSD SCI ignition. When I have this on,when the problem occur the car stalls,but leave it off for 3 minutes and then I start again for another 1 mile or so. When the problem occur really bad,when I pressed the gas the rpm won't go pass 2.5Krpms and then the engine stall. After took the MSD SCDI off the problem still happen but only minor jerking/sputtering once in a while but the engine never stalls. I check the MSD SCI is fine.So far I did is change sparkplug cable,sparkplugs,different coil,4 different ignitor and nothing fix the problem. I ran out of idea now what might be the problem is.

 

what could cause this problem?
do you think the throttle body too.

 

What kind of intake do you have? Well I don't know if this would help you, but something like this kind of happen to my motor and all I did was mess around with the intake pipe (like move it up) and make sure the filter was clean. It worked for me..

Good luck anyways.