mrmint69

I have the car running as strong as ever. I noticed when the car is slightly warm it has great throttle responce with only part throttle. When it really warms up good i notice when i accelerate it takes farther for the pedal to travel for the same response. Anything under 1/2 throttle is less than when cold but after 1/2 throttle is runs the same. Usually meaning i spin the tires more and have trouble getting good starts after a few miles of driving. I thought it might have something to do with open and closed loop but my knowledge of it is small. Thanks for any help.

transAMdriv3r

we cant really tell you for sure, it could be a number of things. the best thing you can do is take it to a mechanic and get it scanned. upon experience it was the oxygen sensors for mine.

OBE1 95Z28

Once the engine warms up, you're in closed loop mode and the O2 sensors help the PCM set the air/fuel ratio under part throttle driving. Chances are your O2 sensors are your issue.

mrmint69

I replaced them yesterday with brand new AC Delco ones. The car ran exactly the same before and after the swap. Could it take some time to adjust and if so how long is normal?

OBE1 95Z28

Shouldn't take any time to adjust. I'd run some monitoring software and check your knock counts.

mrmint69

I don't have any software but i see the cables on Ebay are $90. What do i do need to do besides have the cable and a laptop?

shoebox

From a cold start the a/f is going to be a little richer, so it might feel a little peppier. Maybe that is what you are noticing (not knowing exactly what temp your vehicles' performance seems to change).

mrmint69

Just throwing this out there. I notice when the car is cold the oil pressure is up at 40-50. When the car warms up it goes to 18. I would say until it goes below 20 psi it is the best the car will run. Could the 100K on the motor cause me to lose power since my oil pressure is lower at this point. I drove a 99 with 30k miles and i could really feel the power the second the gas is depressed and mine does the same thing but only briefly while cold.

shoebox

Oil pressure is always going to be higher when the engine is cold, because the oil is thicker and harder to pump. I don't think you can compare to an LSx engine, because they are totally different.