I have a 95 Buick Regal, V6 3.8 Liter. The symptoms are the following: stuttering idle. And lack of response at times when I try to accelerate. Like sometimes I’ll be driving on the highway, and having no problems. Then I’ll be going up a hill at around 55 mph, and then the car will shudder as I try to maintain a speed of 55 mph. So I have to ease off the accelerator and slow down. At first I thought this was a transmission problem, but I’m guessing it’s the same problem that causes my choppy idle.
So I had this acceleration problem on the highway when I was going up a hill. And a weak idle. These problems have been going on for several months now. They were annoying, but didn’t seem that serious. Then all of a sudden, on a rainy day, the car was really responding poorly to acceleration at all speeds. I was able to drive around, but I couldn’t count on the car responding right away when I hit the gas pedal. And the car would shudder at times.
Then, I didn’t drive the car for a few days, and then it was dry, no rain, and the car ran better. So I’m thinking humidity makes the problem worse.
I have also noticed over the past few months, that the car runs best when I start it up after a few days of not running it. Then if I drive the car a few miles and let it sit for about 2 hours or so, it would idle weakly when I would start it up again. The car’s been doing that for several months now, but it wasn’t really affecting the drivability or the response of the car when I hit the gas pedal.
Now it’s gotten much worse. So, I’ve already replaced the following items myself to no avail: mass air flow sensor, oxygen sensor, and egr valve. I’m guessing the next thing to fix is the pcv valve. But I also think it might be the fuel pump. My first guess though is the pcv valve.
What else could it be? And is there any easy way to test to see if the fuel pump is going bad? Or should I just take out the pcv valve and see if it looks bad?