The other day I got on the highway and my cruise didn't work. Then discovered the other day my air direction switch didn't work its stuck on defrost only. And today it snowed and my four wheel drive doesn't work I can shift transfer case but no front wheel spin. The only thing I've done to it lately is change the oil and the fuel filter. And I've never had a.problem with it before it is a 98 24 valve. What is happening to my truck? Is this stuff related somehow?

 

it is related... you have a vacuum leak somewhere, the vac pump is in front of the power steering pump, trace the vac line, and you should find the issue, unlessthe pump has failed, but unlikely

 

I had that happen to me with my 97 12 valve and found after changing fuel filters the supply line that dodgetrucker is talking about goes to a tee under the weather stripping above the filter on the top firewall got knocked off while the filter was being changed..it runs very near it..

 

x2 its a vacuum leak. there is also a vacuum diaphram under the drivers side battery that tends to fail.