Well now im getting frusterated. Ever since I swapped the peanut cam for the one in sig, I've had this "jerking/ bucking" problem at part throttle. only really noticible after the TC locks up. Things I've checked/ replaced:
TPS- checks out perfect- smooth increase from .5 to 5V
CTS - good
New Delco plugs
New MSD superconductor wires
New MSD cap/ rotor
New MSD coil
New dist. gear
No play in distributor
New fuel filter
Not the tranny- checked by tranny shop
New pickup coil
New O2 sensor
New MAF burnoff relay (was getting code 34, now gone)
Checked for vacuum leak with carb cleaner- no apparent leak, I even re-sealed the intake just to make sure.
Doesn't miss under 1/2-full throttle at all, just part throttle (that I can feel).
I don't have a scanner or laptop yet, so I had it scanned while some shocks were getting put on.
They said " everything checks out fine", all the sensors are operating perfectly, and handed me a bill fo 65.00 CAD. big help
I know I have slightly leaky injectors- hard to start hot and gassy smell/smoke, but it was the same with the peanut and never had that jerking/bucking. Sorry for the long post, its been a PITA since August, and it really is driving me nuts.
Thanks in advance for your help,
Jeff

 

Wow, always amazes me when someone says that.."I know this isn't right, but it didn't cause problems before"..
No flame intended, but if you know you have something wrong with the fuel delivery system, why not fix it...you'll eliminate a very likely cause of your problem.

Even if it's not the sole cause of the problem, it could be contributing to it.

 

I hear what your sayin' Mike. The only thing that made me reluctant to just go ahead and change the injectors is that a) it's a PITA, b) they're not leaking bad enough that the FP drops appreciably within even an hour after it's shut off. Don't get me wrong, I am going to change them next month when I got the dough, but could it be something else as well?
Thanks,
Jeff

 

I just had a thought. I ported the plenum (knocked down the walls) at the same time as the cam swap. Could this cause any probs with the egr or anything?

 

I'd say you need to fix whatever problems the car has first, then start pointing fingers. I have run bigger cams than that in previous peanut cammed applications and not had any problems with jerking/bucking at part throttle. Only reason I can think of that its doing it noticeably now and not before is that now you have a real cam, before you did not. Mild cams tend to hide tuning issues.

 

yeah, the leaky injectors may have been efficient for the peanut cam, but now that you're trying to push more power, maybe the injectors are just not cutting it.

Try swapping out the ECM and getting a chip?

 

What does your fuel pressure do at WOT in 2nd gear?
have you even thought about the pump? relay?

 

Little GTA,
I don't know what my FP does at all, I ordered a FP gauge locally, and got some POS with NO fitting on the end at all, just the gauge. WTF am I posta do with that? Anyway, the garage checked my FP, and said it was good. I'm gonna get a laptop, and hopefully some injectors next month if I got the dough- I happen to be moving next month- hoping to have some cash left over. Pump was replaced by previous owner 2 yrs ago- relay seems to work fine for priming.
Thanks for the replies. Keep them coming!
Jeff

 

Couldn't hurt to change the leaking injectors.
Also, I agree with nblanchard about eliminating the ECM and chip from the equation.

Need to get that Scantool on there when the problem is revealing its head.

As far as the fuel guage...either get an auto parts store to help you out, or take it back and get something else. You need to have a long enough hose to tape it to your windshield, or get it into the interior where you can watch it at Wide Open Throttle.