Have a 94 Z with 6 speed..basically i cant go into 6th unless the road is flat with no hills. As soon as it starts to climb the thing bucks and sputters and has the occasional pinging..It will do it in any gear if you stomp the throttle. im assuming a lean condition?? It has gotten progressively worse although it has stayed the same for a while now. Car has 140k on it. Anybody run into his? Fuel filter?

 

If it was a fuel problem (lean), it would probably be due to low fuel pressure. Have you checked the fuel pressure under load?

Exactly how low RPM are you trying to climb hills in 6th gear? Any weakness in the ignition system is going to show itself under those conditions.

 

Getting worse now. Changed the fuel filter and didn't change anything. Basically now if you try to put the hammer down in any gear it coughs and sputters but will drive. 6th gear pretty much useless as at the low rpm it runs like crap. I also noticed it pings while accelerating if you are aggressive. Looks like I will have to take it in and see what codes it's showing.

 

Hmm, every singlke thing you said here could be due to low fuel pressure. Why not check it.....it's pretty easy. Low fuel pressure will not set a code in the computer..

 

Dose it seem to he hesitant to grab 1st gear or shudder more than normal when going into first? If so how old is your clutch?

 

Mine does the same thing occasionally. If I give it gas on a flat it will still miss. Normal driving fine, give it a moderate amount of gas at low rpm/high gear and it will miss.

This happened right after I changed plugs and wires the first time. Turned out the back passenger side plug was loose some how. I tightened it up and it stopped the problem.

I don't know what the problem is this time, but I have plugs and wires waiting to be installed.

So we'll see, Good Luck.

 

ive found that my lt1 doesnt like to be ran under 1800 rpms in 6th gear
try downshifting and see if it still doesn it

 

Clutch is new...500 miles on it. I will dig into the fuel pressure.

 

Mine does it under the same low rpm condition in 5th gear as well. Never had it happen in 1st - 4th that I can remember. Never in low gear at all.

If my plugs and wires change doesn't take care of it, I will start check fuel pressure and hook up Datamaster and see what it's really doing.

 

Probably been answered before but do they sell a gauge that screws to the schrader valve? Anybody have a specific part from napa or? I'm out of town doing this on my phone so kinda hard to search.

 

You can get a fuel pressure test gauge for about $35. -4AN connector that fastens onto the Schrader valve, and has a pin to depress the valve core, and a small valve to relieve the pressure when you unhook the gauge. Rubber hose allows you to pull the gauge up to the windshield, tape it there, so you can watch the fuel pressure as you drive.

 

New info. Last weekend car died at an idle and would not restart. Had to have it towed. Sucks but what ya gonna do. Digging into it: fuel pressure is good at 40 with key on. Pressure doesnt fall off as it sits. Will not start with starting fluid. With air filter assembly off I noticed while trying to start it it is backfiring thru the throttle body. I did pull a plug and they dont look terrible although the gap is about .080..will replace but im sure that is not the reason it wont fire. Would a stuck egr valve cause it not to start? what else can I check?

 

No spark at cylinders 1 and 3 going to dig into testing the opti..

 

If you have spark at the other plugs try gapping the plugs(I'd replace them), and check the wires (I'd replace them too). Ohm a few wires to check for resistance. Then check the coil before even thinking about the opti.

A weak coil, coupled with a big plug gap could give the symptoms you describe, even with a properly functioning opti.

 

0.080" gap is probably at or beyond the ability of the stock ignition to fire. They need to be replaced. With a gap that big, the spark will start to jump between the wires because it can't jump the plug gap, destroying the wires. They should probably be replaced as well.

That could easilly explain the problems you are having.