The other day my 1998 4.6 threw 3 codes. p0171 & p0174 & p1000.
I checked around and believe that i need to replace the vacuum lines/ pcv lines and other hoses. My question is, some hoses look pre formed how do i go about getting them?Also are there other fitting that i should change? Where should i get the hoses and other lines from? I believe that in order to do the job right i should go ahead and replace all rubber hoses going to the motor. So has anyone done this? Do you have a list of parts needed? I feel it is like changing only one u-joint, when you know both should be changed.

 

For inspecting/replacing rubber lines around the engine, pay closer attention to the black rubber hoses and end fittings of the nylon lines. In particular, the PCV line from the valve cover to the rear of the intake, the brake booster line, the two small lines to the DPFE, and the rubber bypass hose from the intake ductwork to the IAC. All the lines at the rear of the engine/intake fatigue from excess heat/oil. The pcv line is usually nylon, except on the ends, and those ends go bad, especially the rear fitting.

As for the nylon factory formed lines, here is yet another use for the Mityvac hand vacuum pump. By plugging one end the pump can be attached to the other and pumped up to whatever amount you want. Any leaks in the line itself or the fitting will show up as a leak down on the gauge pressure reading. The Mityvac can be used to apply pressure to anything working off vacuum and show resulting leaks or good working order.

If you can't find any bad vac lines, check bolt torques around the throttle body, IAC, EGR, etc. Also, any misfit air intake duct work will give the same codes.

It's a good idea to initially check engine vacuum.

Dave

 

the DPFE lines are FoMoCo only they are a special silicone braided lines. most dealerships carry it on the coil and sell by the foot & is pricy. another that is FoMoCo only is a molded line going from the back of the throttle body mount housing over to NEAR the brake booster....generally marked gas or gas vapor. can't really speak for the others mentioned....but those one should be able to pick up and most parts stores.

 

well what i found for now is the line comming off pcv valve to the back of the intake was broken. someone tried to fix it by putting a piece of hose around it. so i cleaned it and glued it with some industrial grade pvc cement. Then i found a block of 1/8 plastic lines by the battery. One of the lines (black one) going into the fender was broken off at the rubber 90 rubber boot. i took the broken piece out of the boot and it looked like it had a barbed end. and just pushed the rest of the tube into the boot. there is a hose that enriched talked about that looks like it is deteriorating. So is it safe to say all these line i must get from the dealer. Im not affraid to spend a lil money to get all the hoses and stuff to fix it right.

 

If those lines are not sealed it will make your truck run pretty rough.