Fuel pressure regulator, check the vacuum source to see if gas is present...

If this symptom does not go away when warm, then I suggest you look @ the timing belt...

 

Make sure you have no vacuum leaks.There are some vacuum tubes that could cause a vacuum leak when cold.The run along the back cyl head.

 

ok thanks guys, wheres the fuel pressure regulator?...

i already had to replace one of 2 vaccum lines that run behind the block, i caught it early . This didn't fix the problem.

 

?.. anyone

 

It's @ the end of the fuel rail...

 

sweet i'll check it out thanks

ive also been told to unplug the MAS (mas airflow sensor) and see how it runs and to unplug the EGR (Exhaust Gas Recirculation) vavle wire and see how it runs, is this also a possibility?

 

ok well im coming to the conclusinon it might be a spark plug wire. How will a car run if a wire is "shorting" not completely bad, but has minimal conductivity?

 

problem solved and fixed

problem (if anyone even cares) : falty oxygens sensor due to my plugged fuel filter. (one problem caused another....)

 

An O2? That's odd. The car doesn't even use the O2 until it's good and warmed up (the whole open/closed loop thing) Should've been the other way around, running great when cold, crummy when warm.

BTW. I really like those Z34s. My sister has a 96. It's a nice car and pretty quick. Hope it runs great for ya for another 140K.

 

Yeah. What was happening is my fuel filter was clogged, so my pump was working extra hard, (i have a very good mechanic, he let me hook it up to a computer and run some tests.) Basically the O2 sensor went bad becasue the fuel would build up in the morning, making it run crazy, the mixture was too rich. It basicaly burned my O2 sensor. Since the O2 sensor was toast, my car would make an even richer mix, and use way too much fuel becasue the O2 sensor monitors the exhaust to tell the car what mix to deliver. Today is a morning of reckoning. Im going to go out and see if its fixed... My mechanic said it may take a few days for the car to get used to the working sensor. (btw i didn't buy the sensor from him, this guy really knows his car and i admire him alot.) Hes always staying ontop of whats current, he takes classes even! I am realy in debt to this guy.

 

I'm surprised a bad O2 sensor didn't cause the check engine light to turn on. BTW, I hope you change the fuel filter more often in the future. It seems like a lot of people forget to change it.

 

its not that i forgot to change it, i keept good maintenence on my truck and i do on my car. Since i bought this car used, i have no clue when things were changed. I did a close inspection of the car b4 i bought it. Didn't look underneath. Just by looking at the filter i could tell it needed to be changed... I replaced the plugs, which actually looked good, but they were a cheap knock off. I put some platinums in them. It still has the origional plug wires.

 

well as of so far, it runs better, but it still runs crappy on the initial start up, and it has died both mornings, on the initail start up. It doesn't rev as high now when i first start it up. It sputter VERY bad though when i acceperate until i get to 3k rpms. It sounds like a old motor boat, or somone running a stick along a wooden fence.

anyone have any ideas??? im running out of ideas, and im getting frusterated.

 

My LQ1, 3.4 DOHC, had similar problems for a while. I had an aftermarket 3 month warrenty and had to have the MAF, O2 sensors, and whole computer replaced. Luckily GM covered the computer replacement so no cost to me, the warrenty didn't cover it. I would say maybe the plug wires, did you replace the upper intake manifold gaskets when you changed the plugs? On my, 96-97 LQ1, you have to replace the gasket each time you take off the manifold. If you need the gaskets I got both upper and lower gaskets for less than $70 at NAPA when Autozone wanted $120 for just the upper. Best of Luck.

 

yeah i need to somehow obtain an ohm meter and check the plug wires. When i replaced the actual plugs i did no work on the intake, beacsue i used my awesome mechanic skills to get the plugs in without having to take anything off . It seems everything for this car is killer expensive.... timing belt i looked at was 130.00, plug wires are 100.00, 02 sensor was 50.00 and the Cam sensor was 90.00. Im really frusterated!!! I will try and check the plug wires. Does anyone else have any ideas?

I appreciate all of the help!

 

When i replaced the actual plugs i did no work on the intake, beacsue i used my awesome mechanic skills to get the plugs in without having to take anything off .

Be glad you have the 95 then the 96-97 intake has to be taken off to get at the plug wires, it sits over the spark plugs and wires with very little clearance in between for any mistakes. Kinda sucks but hey whatcha gonna do.

 

Be glad you have the 95 then the 96-97 intake has to be taken off to get at the plug wires, it sits over the spark plugs and wires with very little clearance in between for any mistakes. Kinda sucks but hey whatcha gonna do.

even with the handy engine puller? what you do is take off the front mount from the frame to the engine, put the V puller in and tighten the bolt on it, it pulls the eingine forward. (i actually didn't even need the V puller, i barley snuck the plugs and long plugwires in )

 

Ok, after a drive home, and some work. Ive figure out the problem finally. The computer is messed up. It has 2 modes, one for startup and one for operating tempature. Something (not sure) is wrong with it. The mode that controls startup is f*cked. So im going to replace thatt this week.

When replacing the computer, do i have to get it programed?

Unfortunatley i have another problem. My tail lights don't work. The blinkers work, and the "running" lights work on the tail lights, but the only light that works when i apply the brakes is the 3rd brake light. Checked fuses, all are good. What gives?

I also notice (dear god will this ever stop...) that my headlight was out on the way back to school!!!!!! (it was rainig) Could my computer be messing with this? or wtf is my luck just bad??

NEED HELP!!@#!@#@!$

 

The computer doesnt control the headlights(Unless they are automatic but even then it wouldnt cause that kind of problem).

 

yeah i need to somehow obtain an ohm meter and check the plug wires. When i replaced the actual plugs i did no work on the intake, beacsue i used my awesome mechanic skills to get the plugs in without having to take anything off . It seems everything for this car is killer expensive....



I have a friend who had a 1992 Lumina with one of these engines and he commented that ever time it needed something it was super expensive. He never could get the service engine soon light to turn off. He finally got rid of it because it just was too expensive to keep fixing.



timing belt i looked at was 130.00, plug wires are 100.00, 02 sensor was 50.00 and the Cam sensor was 90.00. Im really frusterated!!! I will try and check the plug wires. Does anyone else have any ideas?

I appreciate all of the help!

Good luck.

 

The computer doesnt control the headlights(Unless they are automatic but even then it wouldnt cause that kind of problem).

The MC Z34s all have auto headlights, so the computer would control something.

 

ok, yeah the bulb must have just went out then. My lgihts aren't auto, 1996 is when they started auto headlights.

does anyone know if a new computer needs to be programmed?

 

Yah, it will. I had to have the computer in my 98 replaced. They swapped out and reprogrammed the computer. Cost me a little over 500 bucks if I remember right.

I won't even mention the fact that they forgot to tighten down the negative terminal from the battery which cost me a tow and a half hour of tech time to diagnose the next day. heh

 

Yah, it will. I had to have the computer in my 98 replaced. They swapped out and reprogrammed the computer. Cost me a little over 500 bucks if I remember right.

I won't even mention the fact that they forgot to tighten down the negative terminal from the battery which cost me a tow and a half hour of tech time to diagnose the next day. heh

500 dollars?!@?$@!?#@?# you have to be kidding me, i do not have that money!#!@

the computer new from napa is $100.00

If i just put the PROm chip in from my old computer, won't the new computer just relearn the specs???

 

ok well i talked to the local dealership and local napa guy. they both said all i should need to do it take the old computer out, put my PROM chip into the new computer, hook the new compuer up and it should work.

sound right to you guys?