Big tuneup coming - need advice


#1

Recently had a #1 plug misfire on my 2000 Ford Expedition (5.4 L, 150000 miles). When I pulled the plug, it’s obvious that they’re the original plugs. Sooooooo……
Bought new plugs and COPs for the other 7. Also bought rebuilt injectors since they’ll be easier to replace than clean (& just as cheap). What else should I figure on doing at that point?


#2

You should do whatever else is called for in the maintenance schedule that came with the vehicle.


#3

Agreed. Remember to gap your plugs properly. Lotta people forget that step when they’re replacing them.


#4

Air filter, fuel filter, PCV valve, coolant, transmission fluid, brake fluid, PS fluid, differential fluid, check belt and hoses, and check suspension for looseness. Basically a good inspection. Can’t quite see the picture of why you’re replacing injectors though.


#5

Always run a compression test when any tune-up type maintenance service or engine performance problem exists.

When installing the new plugs snug them up only. Do not overtighten them and in reality, you should not even use a torque wrench. Torque wrenches (especially 1/2" drives at low settings) are notoriously inaccurate and many published torque specifications are from another universe. Example, and from a manual for a Ford 4.6.
7-14 Ft. Lbs. That’s the equivalent of throwing a grenade at something. The 7 is sort of tolerable but the 14 is too much and can strip or pull threads.


#6

Just be careful when you gap those platinum plugs. You could easily fracture the tip if you wedge against it. If they need adjustment, use a gapper that just bends the hook end without touching the tip.


#7

Yeah I’m with Pete. Injectors are good for 4-500,000 miles. No need to change unless a problem. I’ve never had to replace an injector. If you got the titanium plugs, DO NOT GAP THEM-they are too brittle. They are already gapped.


#8

I got a deal (through family) - 8 injectors for $100. Can’t have my injectors cleaned for that price & I’m buying an extra 150k miles of reliability by doing it now. Have to remove the fuel distribution hard lines to do the plugs which makes it like a 10 minute job.


#9

I think 150K on the plugs is the problem. I don’t see a need to replace all the COP’s but it can’t really hurt either. If you have the bucks and time to replace all this stuff the Explorer should run great. Don’t forget to put some money into new filters, especially the air filter. IF the plugs went 150K, god knows how long that air filter has been in there.


#10

Change the thermostat if it’s over 5 years old.


#11

You should always replace the coil boots. I have seen many of these jobs result in dissatisfaction because the old boot cracked when pushed down on the new plug.