Just doesnt feel right...

[NitrousJunkie]

I have a 94Z and it just doesnt feel like its running right at the lower rpm's, especially at idle once its warmed up, it will idle and then drop down about maybe .500-.600 rpm's at a stop sign and then go back up just not a solid idle, it also just doesnt "seem right" in the lower RPM's but the high rpm's it seems to run great, I'm thinking MAF or OPTI, I've already replaced the pump and plugs.

I'm pretty picky so maybe I need to chill out but I figured I'd ask.

Any idea's?

Much appreciated.

[Z28pr0jekt]

you replaced the plugs, did you do the wires also?

check the fuel pressure

[NitrousJunkie]

I havent done the wires yet, thats next.

I'll check the FP tomorrow, 43.5 correct?

[Z28pr0jekt]

I havent done the wires yet, thats next.

I'll check the FP tomorrow, 43.5 correct?

FP is 43.5 with the vacuum hose disconnected

[IronOutlaw]

Do you still have a cat? Disconnect it and see if it runs any better at low rpms. Sound like my car when my cat was slightly stopped up.

[NitrousJunkie]

I really need to invest in a A/F monitor and get a data logger, I feel like I'm walking through a maze blindfolded.

[nickp]

is this a recent problem? my car acted like that after i put a ported mass air sensor on it.

[NitrousJunkie]

Yeah just started, just doesnt sit at idle like it should, drops down slightly then back up about every 10 seconds.

It's not a huge drop, it just bugs me and along with it not feeling 100% alive in the lower rpm's, like its only running off 6 out of 8 cylinders, Im dying to spray the car but I can't until I get it running perfect.

[Z28pr0jekt]

do you have an underdrive crank pulley on it?

[KissMyWhtSS]

Fuel pressure sounds alright. I'd check the voltage at the coil, pull a couple plugs to ensure they are good and properly gapped and ensure all wires are routed correctly and on the plugs tight. That should help narrow out a few common problems. Does it start strong or seem weak?

[NitrousJunkie]

No Underdrive Pulley.

Starts Strong, better than ever with the new pump and plugs.

I'll check the voltage on the coil, I think I have a bookmarked info on how to do that and also pull a couple plugs to check to make sure there gapped right and also check the plug wires.

It didnt do this right after the new pump install, in fact it ran better than it ever had before, it just started this about 2 days ago.

[KissMyWhtSS]

out of curiosity, how long has the pump been on it? Your fuel pressure is fine so I doubt this is the problem, I'm leaning towards spark.

[Z28pr0jekt]

out of curiosity, how long has the pump been on it? Your fuel pressure is fine so I doubt this is the problem, I'm leaning towards spark.
He never said what his FP was, he asked what it was supposed to be and I re-affirmed that... so we still need a # for that

[KissMyWhtSS]

He never said what his FP was, he asked what it was supposed to be and I re-affirmed that... so we still need a # for that
Damn my bad, I saw "FP is 43" and scrolled down and kinda crossed that idea out. Thanks for pointing that out.

[Z28pr0jekt]

haha i had the feeling that was gonna happen with the way I posted it

[Toronto_LT1]

check your MAF aswell.i had a problem like that before and it turned out the MAF was dirty.

[NitrousJunkie]

Will the pressure be a steady 43.5? Want to make sure before I check.

Fuel pump was installed less than a week ago.

I thought about the MAF, thats actually the second thing that popped in my head after what every other LT1 owner automaticly thinks....the opti.

[Z28pr0jekt]

Will the pressure be a steady 43.5? Want to make sure before I check.

I thought about the MAF, thats actually the second thing that popped in my head after what every other LT1 owner automaticly thinks....the opti.

Unless you have a lopy idle or an idle that is constantly going up/down/up/down which could possibly mean the IAC is opening and closing... the pressure should be fairly steady.. but remember to take the vacuum hose off when measuring for 43.5

[Tyler Wheat]

I was kind of confused as to what your specific problem was in the OP.

If the problem is with a fluctuating idle, I'd clean the IAC valve and check for any vacuum leaks around the intake.

If the idle is rough, there's a ton of things that it could be. You're going to be shooting in the dark unless there is an SES light on. Even then, that may not be the problem. All the others have already mentioned all the basic things to check, but its more than likely going to take some time to pinpoint the problem.