2WD Expy 4.6-Slow Acceleration

Thanks guys!

It was a fresh engine.

I will test out the exhaust restrictions today. Might check the plugs too.


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Alright so I check the vacuum/exhaust leaks and it seems that everything is running fine. The reading was about 19in, but I will check it 1 more time to just make sure I was testing the correct vacuum part.

I did notice something about the EGR valve though, and I am not sure what it is supposed to be doing.

The little green vacuum hose that goes to the top of the valve feels like it is blowing air out, but in short little puffs. I am not sure if that hose is supposed to be doing that or if it is supposed to be a full on push of air. Or maybe its supposed to be sucking air? Im not sure.

Thanks for the replies guys! Glad you didn't forget about me!

Watch the video, 19 inches is low vacuum. A fresh engine should be in the mid to high 20's.

I watched it, but I will check it again to make sure I got the correct reading.

Any ideas on the green vacuum hose?


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If it is the one that has a 90 degree elbow at the end, it is a vacuum line.

Just found a vacuum leak. Going to try and fix it!


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kindly say where the leak was or post a pic it may help others

Of course! I was planning on doing so, but I wanted to get home first

The vacuum leak was in the back right side of the throttle body. This was because of a loose screw(no idea how I missed this the first 3 times I checked it)

What I did to find this leak was to spray brake cleaner around all the areas where there could be a gap. So I left the car on, in park, and then began to spray the brake cleaner around the throttle body. As soon as I got the the back right side of the throttle body, the car started to sound like it was going to stall for a few seconds, and then returned to normal. That is how I knew there must have been a gap there.

My Results: After fixing this issue I went ahead and reset the learned memory in the PCM, and hit the road. Right away I saw a very very big improvement in the acceleration, and power, but it was still not as good as it was before.(might be because the PCM was still in its learning mode)

My Next Steps: I am thinking of either bringing the car to a trans shop to get the trans checked out since it hasn't been looked at for 195k miles.... or taking it to the dealership, and having them scan the PCM to see if there are any issues with it(or even flash it), and maybe even go into mode 6 to check cylinders and all of that stuff.

What do you guys think? Let me know.

I had a longer write up, but my internet decided to crash and deleted the whole post, so this is my second attempt

Well now that you found the problem at the throttle body what are your new vacuum readings and again kindly post a pic of the screw you found loose