Brake Booster & Plugged Cat

[BCCHowdy]

Hi everybody. I'm battling two different issues with my truck. I'm hoping for a little encouraging advice. I'm driving a '03 1500 QC 4x4 4.7. My mileage isn't doing too bad, but my power and throttle response has dropped significantly. Here's my thoughts: Brake Booster: I thought maybe I had a vac leak and starting plugging into things with my vac pump to see if they would hold a vacuum. I can't get my brake booster to pump up and hold anything at all. I have no problems with my brakes, but every morning the brake pedal is hard which is a clear indicator it's bled down. Any other non-dodge booster I've plugged into will draw vacuum and at least slowly drain down while I'm watching it. Is there something particular about these boosters, or is this normal? Would anybody with a vac pump mind plugging into their booster to see if they get the same effect? Cat: The truck has just over 88,000 miles and it has the original cat on it. I'm suspect it may be time for replacement. The only way I've read to test the cat is by smell, which I don't notice anything, or by using a heat gun. The theory with the heat gun is the cat should be 200 degrees hotter than the rest of the exhaust pipe. I drove my truck home from work (about 15 mins) and did a temp reading while it was parked idling. The pipe is about 420 degrees. The neck where the cat starts is just over 500, the body of the cat is 420, and the neck exiting is again around 500. The pipe after the cat is 420. Thoughts on this? If it needs to be replaced, is it worth replacing or putting in a section of pipe and getting an o2 simulator? Vac Gauge: I put a standard vac gauge on. At idle I'm pulling just over 15". As I crack the throttle the vac drops and returns to 15. As I rev the engine up the gauge goes up around 18" (no load between 2000 - 3000 rpm). When I snap the throttle closed it jumps to 21-22 and returns to 15. These seem low to me. Thoughts? I know I asked a mouthful in my first post but I'd really appreciate any thoughts or similar experiences. Thanks for the help!

This ad is not displayed to registered and logged-in members. Register your free account today and become a member on Dodge Forums!