jerky car in traffic type driving...
 

I know ive had a similar issue with my civic that I was able to mostly correct via tuning... but i'm having it with my talon, and its worse, and my talon is stock.

Symptoms: when i'm driving in traffic (1st or 2nd gear, on and off the throttle) the car is REALLY jerky when i go light throttle to no throttle, and vice versa. Like ridiculously jerky, so most of the time i just end up clutching, which is a pain in the ass.

Car: 92 talon TSi awd
mods: charge piping and FMIC, 3 inch turboback, walbro fuel pump, HKS air can.

Anyone know what could be causing this? This wouldnt be an ISC problem would it? I know my ISC is shit. New spark plugs, throttle body is clean, gets decent gas mileage (21-25 mpg). New Bosch O2 sensor. I dont know whats going on.

the car MIGHT have some vacuum leaks, i have a pretty good suspicion. Could that be causing this?

Can anyone help? Thanks.

Re: jerky car in traffic type driving...
 

I would definitely do a boost and vac leak test. Also, if you know your ISC is shot why dont you relace it?

Re: jerky car in traffic type driving...
 

trying to get someone to actually sell me one that is working properly.

Re: jerky car in traffic type driving...
 

i'm thinking maybe this is the idle switch? after looking at the link that berda posted on testing sensors... hmmm

Re: jerky car in traffic type driving...
 

I have a boost leak tester, it works really good, I might be intrested in selling it or letting you use it. If your around the st cloud area call me. 320 230 5524 , erik

Re: jerky car in traffic type driving...
 

Easy to build a boost leak tester at Home Depot, everything you need is there.

Re: jerky car in traffic type driving...
 

Yes, I've already had one made for years... and i've already done some boost leak testing on the car, havent tested past the throttle body though... i know theres a huge boost leak by the turbo somewhere (or maybe it is the turbo itself).

ANy common areas where dsms leak vacuum?

Re: jerky car in traffic type driving...
 

My car had a slight leak at the throttle body gasket, replacing that remedied the problem, did you check the hose where the B.O.V vents back into the intake? Mine had a leak there, tightening the hose clamp with a socket fixed that one. I've never heard of the turbo itself actually leaking boost. Is your intercooler piping on all the way and tight? Mine unclamped one day and the car was doggy and I couldn't figure out why, well I checked under the hood, and since I just installed new plug wires the day before, I thought that might be a issue. Well as I was looking I noticed my intercooler piping was off on the turbo. Reclamped and car ran great. Well let me know what you find out.

Re: jerky car in traffic type driving...
 

Oh, did it do it before you put the walbro on? If not maybe your pump is flowing to much fuel for your injectors to handle? Just a thought, maybe not the problem.

Re: jerky car in traffic type driving...
 

isnt that what the fuel pressure regulator is for?

Re: jerky car in traffic type driving...
 

i have a boost leak tester BTW, but thanks for asking.

Re: jerky car in traffic type driving...
 

Yes but due to the increased fuel pressure your regulator might not be holding up. Some people experience zero problems, others do. It seems pretty much hit or miss.

Re: jerky car in traffic type driving...
 

So have you figured out your problem yet? Let me know how the battle goes, don't worry every problem has a solution.

Re: jerky car in traffic type driving...
 

thanks man! Maybe i'll look into a FPR. I know with my civic I didnt really need an aftermarket one to keep the fuel pressure under control, also running a walbro 255 hp.

I'll keep you updated!

Re: jerky car in traffic type driving...
 

I'm not saying that your problem is your FPR, I was just letting you know. Dont just go and replace it based on what I said. Although it is a good investment it may not be your problem.

Re: jerky car in traffic type driving...
 

naw, its a good investment, i would be doing it eventually anyway. But good advice, i might just invest in a gauge first.