Dustyv8

Hey all! Need a little bit of help Ive tried searching a bit but I cannot narrow down my problem. My car is 95 Z28 6 speed, 155k. The car has been really good to me never leaving me stranded anywhere or acting up to much.

EXCEPT When it gets cooler out if the temp outside is below 70 degrees the car feels very weak and stutters until it warms up itself during this time it will throw a check engine light then that goes away when everything gets warm.

Any idea would be welcome, the car had a so so life before me and im slowly trying to bring it back up to snuff.

ZFreie

Have you scanned for the code?

Dustyv8

When I first got it my mechanic put it on the computer and didnt get any codes in return. I might need to take there again on the next cold day and do it again. Course any ideas now would be great.

Bigtoyz

iTrader: (2)

kind of acting like the open loop might not be quite rich enough for that temp. Has it always done this? Has it be modded or tuned before?

Reason why I say this cause mine has done the same thing once it got colder than 65 degrees till it warmed up. I fattened it up a little and problem went away.

Just a throwing idea's out there.....

Dustyv8

It seems like its always done it, right now for mods its got a hooker cat back and trick flow intake and elbow.

Think it could just be a dirty filter or something relating to fuel?

Bigtoyz

iTrader: (2)

If its been awhile since you changed the fuel filter I would do that also while your at it. I would check to see what your fuel pressure is doing if you havent done so also.

But anytime you open the intake flow some and increase exhaust flow.....you need to add more fuel cause your adding more air to your system.

I see your from MN ........I'm over by SD bourder by Brookings.

Dustyv8

I dont think the people that had it before me ever changed the filter I do have one ready just need time to do. How do you go about checking fuel pressure with the car running? Also would it be a good plan to buy an adjustable regulator?

Yes I live right on the MN Iowa boarder very boring flat land. About 2 hours or so from Brookings.

FormulaJoe

iTrader: (5)

You would have to borrow or buy a fuel pressure gauge and screw it on to the schrader valve which is located on the rear fuel rail crossover right next to the fuel pressure regulator.

"Put the pressure gauge on it, start it up and let it idle. Remove the vacuum compensation line from the fuel pressure regulator (cover the end of the line so there's no vacuum leak). Fuel pressure without the vacuum line should be 43.5psi. Factory specs are 41-47psi.
Tape the gauge to the window, and take it out on the road. Run it up to max load/RPM. The fuel pressure should stay at 40psi or higher. Anything less and the pump is weak."

Copied that from camaroz28.com. Injuneer posted it..

Oh and hello from the cities!