horcpowr

I have a 93 z28 130k A4. Last year i went 13.61 @100 with a 1.98 60' on et streets and stock converter.It has a shift kit,3.23 gear,hooker headers and exhaust,no cat,air foil,1.6 rr's but all other internals are stock to my knowlegde,moroso CAI. So this year i added a walbro 255 because the stock pump went bad. I also added a yank SS3600 and a PCMforless tune. Went back to the track and ran a 13.43@99 with a 1.92 60' on the same tires as last time. I know i should be in the 12's with this set up. My car runs rough at an idle, the idle, volts and oil pressure go up and down at the same time. Not real bad but enough to bug me and fell rough. I have replaced the plugs,wires,icm,egr,coil,map sensor,tps sensor and as stated above the fuel pump. The car also has a spot around 5k where it think for a second and then from 5k to 6k it pulls hard again, when it shifts into third it falls on its face and feels slower than first and second. It is not the tune either because i pulled that and slowed down three tenths. Only thing i can think of is possibly the opti is going bad but it tested fine when my friend scanned the computer for me. Any ideas are appreciated and thanks for everyone's time.

duh

iTrader: (16)

It could still be in the tune....just because you drop et. with it doesn't mean it's right. You're best bet would be to call them and describe whats happening....it sounds like it runs out of fuel at 5K rpm. kinda tough to figure out since it's so spuradic, but if you only have 1.6 rockers, you shouldn't have any type of rough running.....at all.....unless you're cammed it should still idle like factory....if it doesn't check sensors and start talking to PCMforless

horcpowr

Very true and thanks for the input, however it runs the exact same without the chip in it. Just slower. Any other ideas are greatly appreciated too. Could this be a bad lifter? I don't hear any significant noises.

duh

iTrader: (16)

you could have a lifter collapsing, but you probably wouldn't have it come right back lie it has been. When did the problem start? Try and remember what you had done right before it started running like that. That will give you a little bit of an idea where to start looking. As for a straight diagnosis.....I don't think there is one since you have a really strange symptom....

lt1-xjs

Sounds like so sort of vacumm leak to me, I would check the hoses to the things that were replaced. The egr is usually tuned out and blocked off, check with Alvin on your tune. You also replaced the tps, check the voltage it may need adjusted. A 160* stat is required. The addition of the stall requires adjustment of the t/v cable at the tb for the trans to work properly and finally, shift points are controlled by the governor. A large aftermarket trans cooler should also be installed.

horcpowr

Forgot to mention it does have a 160 stat, it does have an external trans cooler but don't know what size. This problem started right before the fuel pump started going bad about two or three months ago. The TV cable may have something to do with it falling off when it hits third gear but i know it wont affect the idle. How do i adjust that cable so that it is right? And i will also try to check for vacuum leaks as well. Thanks for the input guys keep it coming because this is pretty aggravating and i want to fix it asap.

1993 z28 f1

iTrader: (6)

Hey:

Whats the condition of the Alt and Sep belt, my car had a miss at 5k with the a/c on around 125,000, lights on.
drove me nuts turned out the alt was going bad shorting out inside. Also all plug wires good they will do that to you as well.

Dub

horcpowr

Thanks for asking,it does have brand new msd wires, and i just replaced the alt about a month ago and re checked the new one after it was on.