This is a post meant for the few on a.cc who know what they are talking about with cars.

Basically, what should be done in an engine overhaul/tune up? My celica has a (Toyota) 5S-FE engine, if that helps at all. Not much as far as maintenance has been done on the car (before I got it), and all I've done is dumped some fuel injector cleaner in the gas tank, done an oil change, and put a new air/oil filter in.

The car idles a little rough and sometimes feels like it has a lack of power. I'd think a tune up would help this situation out (there's nothing wrong with the engine aside from a small oil seep, which should be fixable by changing a gasket or something). Also, is it possible to adjust automatic transmissions at all? Something seems to shift aggressively, and usually it shifts before reaching 2500 rpms (unless I manually shift down or turn off overdrive), which also seems to cause crappy acceleration.

I'm not sure what could be done to tune up the engine to make it run a little better (some googling led me to taking the injectors out and having them cleaned at a dealership or garage, tightening up the throttle assy a little bit, and some other stuff like that).

General tips and advice are appreciated. I'll give cookies too.

I figured it was worth posting here first, because we have at least a couple people knowledgeable about cars, at least it appears that way from the Deathwish threads we get into.

The ones already mentioned plus spark plug cables and fuel filter. A bad set of spark plugs is quite often the source of bad running. I replaced mine and now it feels like the engine (XU9J2, 125hp/177Nm) has 10hp and 20Nm more. If the car feels like it stutters when accelerating, replace the fuel filter. A clogged fuel filter drops fuel pressure in the supply rail (while increasing pressure on the pump side, stressing it unnecessarily) and fuel flow rate. That can cause lean burning, which can ultimately lead to the pistons melting.

It's almost due for an oil change again and the air cleaner is only a few months old. I'll put a new spark plugs in next oil change (in a few weeks), and a new fuel filter.

And my brakes are good, so they can handle it. ;P

Is there anything more you can tell us? What year is the car, how long have you had it, what's the mileage, how did the previous owners treat it, what general condition is the car in, etc.?

if your lacking power that was there before. i would check the exsues system and the timing belt they have the most to do with power.

Yeah, you'll certainly know if the exhaust is leaking. As for the timing belt, if it's one notch out either way, the engine could theoretically run, but it would be as gutless as anything. So I doubt that's the problem. If you're not going to replace the spark plugs just yet, at least pull them out and give them a good clean. You can actually tell quite a lot about how an engine is running from inspecting its plugs, so have a look. You can supposedly tell if the engine (or a particular cylinder) is running too lean or rich, so perhaps that's a good way to tell how well the injectors are working.

All there is to it.

Could be a crack in the fuel intake tube inside the tank or your fuel pump is its way out (the hydrostatic pressure of a full tank forces more fuel to the pump)

The wheel type thing is the throttle cable wheel, which the throttle cable rotates and which in turn rotates the throttle butterfly inside the throttle body.

If the cables both go in the same direction but on different sides of the wheel i'd guess the other cable actuates the kickdown. Or you could have a motorcycle-style dual throttle cable system which i doubt since i've never seen one on a car before. Usually there shouldn't be much slack in any throttle cables, however the throttle butterfly should rest on its stop, the cable shouldn't exert any force on the wheel at idle.

If they go in opposite directions (i.e. both cables would rotate the wheel in the same direction) then i'd be inclined to believe the other one is indeed for cruise control.

edit: See the attached image: Do you have the cables set up as if you had two of same color or one of each color?

I wouldn't know, it depends how they manufacturer has intended these things to be looked at.

For them to be throttle and cruise control cables they'd need to be on opposite sides or travel in quite an unusual configuration - the curved arrows demonstrate direction the wheel would turn if the cable of same color (straight arrows) would be pulled (in the direction of the arrow obviously). You should trace the cables to see where they go.

If the gas pump is weak it sucks. No, it doesn't.
As jhuuskon pointed out, the full tank helps with the pressure. But an empty tank might do the opposite. Do you notice a "Swooosssh" sound, when you open the cap to the tank? I used to have that sound on my Toyota Carina 1991, before rust made small cracks in the tank and the filler neck. I recently replaced the neck. Couldn't stand the gas smell, when I filled up the tank. I got back the swoosh sound. Now it's gone again.

Anyway, when pump sucks gas, it develops a great underpressure in the tank and that sucks!

I hear a swoosh if the tank is below about a half a tank too.

It seems to get power back after I let the pressure out, but I haven't test driven it yet.

Also, jhuuskon, the throttle wheel has the throttle cable actually on bottom, and when you open the throttle up it pulls on the top cable.