There are a lot of mechanics out there who just just retire.
A friend of mine was having trouble with his truck, and much of the trouble was self-induced. He had tried to "mod" the truck and that was half the problem. Sometimes it is best to leave well enough alone.
His wasn't happy with the power output of the truck, so he went down to see old Billy-Bob who has a collection of old muscle cars and pickup trucks from the 1960's and early 1970's. Billy-Bob loves working on older cars, tinkering with carburetors (which means, essentially, replacing them with a rebuilt one) and hopping them up for more power. It was possible to do that back in the day by changing a cam or playing with the induction, but newer cars are pretty maxed-out in terms of headroom. Better to leave well enough alone.
So, my friend installed a cone filter and then never cleaned it. The truck wasn't fast enough for him, so Billy-Bob suggested a pair of headers for it. Headers are basically thin-wall steel exhaust manifolds that are "tuned" by having each pipe exiting the engine the same length - thus the tangle of tubes involved. The problem with headers is that the steel tubing is far thinner than the cast-iron manifolds used on production cars, and tends to rust out. Cheaper headers may leak where they attach to the cylinder head as the mounting plate warps.
For a racing car, where the engine is rebuilt on a monthly basis, headers are not an issue. For your daily driver, which you want to keep running for 15 years, it is. Anyway, the headers started to leak and he went to a second mechanic to have stock cast iron manifolds re-installed.
Now the fun begins. You see, that particular motor used an AIR system - Air Injection Reaction or Secondary Air Injection as it is sometimes known, to control pollution. A small air pump is driven by a pulley and pumps air at about 30 psi into the exhaust manifold, to oxidize (burn) unburnt hydrocarbons. It has fallen from favor in recent years, as you might imagine, unburnt hydrocarbons are wasteful if burned in the exhaust manifold. Modern mutli-port fuel injection systems - and direct injection - do a better job and, as a result, AIR systems are less common.
Of course, if you injected air into a "header" it would burn through the header in short order. So Billy-Bob tore out the AIR pump, valves, and plumbing (but inexplicably left the intake silencer intact) and threw them away and didn't tell my friend. So when the new mechanic put in the stock manifolds, he had to plug the AIR connectors with threaded plugs. Again, he didn't tell my friend about this.
When I went to check this all out, it was a bit of automotive archaeology. The AIR intake silencer was unbolted and dangling in the engine compartment. When installing the headers, mechanic #2 had removed a vacuum accumulator and left it on top of the engine. Ford has long favored vacuum actuators for HVAC controls, and they have this vacuum "accumulator" under the hood. In older Fords, it literally looked like a coffee can. Mechanic #2 unbolted this to get it out of the way to install the new manifolds and then forgot to re-install it. And needless to say the fasteners were long gone as well.
There were other aberrations. The #8 sparkplug wire was melted and someone had repaired it by wrapping the melted portion with duct tape (Ford Rotunda Part #F4PZ12259D). The water pump had been replaced at one point, and someone didn't re-attach one of the nuts holding the A/C compressor mounting bracket in place. There were a few other fubars as well - wiring harnesses moved to access parts of the engine, and then not re-attached. The mounting bracket for the ignition coil dangling unattached (unattached when the headers were installed and then never re-attached when the OEM manifolds were installed). It was a hot mess, but it was running, anyway. Not well, though.
One problem with this scenario is that the exhaust gases will be a bit rich with the AIR system removed, so there is a possibility that the catalytic converter may clog over time (maybe why the owner is complaining about low power).
Now granted, much of these problems started with the owner trying to "monkey" with the truck, falling victim to the siren song of the aftermarket promising to "unlock hidden power!" in the vehicle, when in fact, most of these bolt-on add-ons don't add much. Compounding the problem was his redneck mechanic who didn't understand modern fuel injection and emissions systems - and didn't want to learn, either. My friend's truck was pretty old, but even back then, it was hard to remove one component of an integrated fuel injection/engine management/exhaust emissions system without affecting another part of it. Many systems go into a "limp home" mode when there is a problem, and I suspect my friend's truck has been in that mode for some time, now.
With more modern vehicles - forgetaboutit! Rather than trying to out-Engineer people who have spent their lives designing and building these systems, a better approach is to try to maintain the system as best you can. And one thing I have learned, the hard way, is that some part or bracket or fastener that seems to make no sense, was put there for a reason, as without it, some sort of problem will develop over time - maybe not right away, but over time.
I was riding in the back seat of the hamster and noticed that the seat belt bracket - where it bolts to the floor, has a small piece of velcro-like cloth glued to the side of it. Why? Well, when the belt is buckled, this bracket rubs against the side of the seat. A tiny thing, but without this velcro, you'd have torn upholstery in a year or two. Everything on a car has a reason for being there and before you rip out stuff, think about why it was put there in the first place.
And again, racing stuff is fine and all, but race cars are torn apart and rebuilt after each race. Your daily driver, isn't.
UPDATE: This AM the truck won't go into gear. I look and the brake lights are not working. Turns out the same mechanic put in a new master cylinder but screwed up the installation where it attaches to the brake pedal - and brake light switch. We bought a new switch and installed it according to the mannual.
He returns an hour later, the truck misfiring and making no power. We replace the spark plug wires and cap and rotor. Two of the wires were melted, one was not conducting (the one wrapped in duct tape). I put on a new cap and rotor as they seemed pretty arc'ed up.
So, cross our fingers it is fixed, but if it was my truck, I would find all the missing parts at a junkyard and put it back to stock! I advised him to sell the truck and buy something newer.....
UPDATE: Still broken, no word why. It is melting the new spark plug wires. We also noticed that the oxygen sensor is missing - removed by Billy-Bob! This puts the truck into "limp home" mode, which is why it is running so poorly. At this point, you would have to go through the whole engine and un-do all the "fixin's" they did to it - and find all those emissions parts in a junkyard. I suspect the "power loss" is something else - low compression or a burnt valve, which is how this whole mess got started.
Sadly, the owner just wants the magic bullet - replace one part and it's fixed! That is how he got into this pickle in the first place!
