Fault finding help.

Hi Guys.
I need some advice. I'm three months and three garages into this problem with no-one actually seeming to take the issue seriously.
I've got a 4WD double cab gen 1 Tacoma. She's getting about 100 miles to a tank. I don't think she shifts until about 3500 RPM and despite being equipped with a supercharger and 7th injector I can hardly pull away from the lights and freeway speeds are terrifying. It's like there's no traction in the rear wheels, which I am starting to suspect might actually be slippage in my gearbox. Tacoheads, please help me!

 

This doesn't make sense. Gearboxes, I'm assuming you mean either of the diffs or transfer case because the only real gearbox is a steering gearbox, don't slip unless their gears are physically broken off. But at that point, your teeth are gone and the leftovers of your gears will be free spinning. The only thing that could possibly slip is the automatic transmission. I think you should start by servicing your transmission. if you haven't done that for a while, more than 60k or so, do it. The fluid is probably so gummed up it's causing problems with the shift solenoids and internal clutches. While you're at it, change the oil in your diffs and transfer case with 85-90 GL-5 gear oil.

Which comes to the second point of the problem. If the vehicle is old enough, your shift solenoids may be worn out/heavily used. you might want to change them as well while your doing the tranny service. Mainly because if you decide to change them after the service, you'll have to pay them to change the fluid again, up to you. They're expensive and I'd say it's a 75/25 chance that they're still good since they're just pressure sensors that, I believe, work off your vehicles velocity in relation to the engine load.

Start with those first. My first point about your tranny service easily explains the 100m/tank issue as well, with the gear oil change being a small part of it. Good luck!

 

Thanks man. That really helps.

 

It's got to be the bands in the auto tranny.

 

if 3 different garages don't think what you describe is a real issue then you must be going to mickey mouse garages. are you going to a 5 minute oil change place or something?

any "competent" shop would check it out, road test it, and hook it to the computer if need be to find your problem and quote repair costs

 

Okay, well now I'm through with four different garages. Apparently there's nothing wrong with the TPS or the transmission but the guys that installed the supercharger charged me for an engine overhaul they didn't do and installed the wrong kind of oil in the supercharger and the wrong type of sparkplugs so that's been some small improvement. She's still seriously lacking power though and seems to get about 7mpg. She can get to freeway speed if I absolutely floor it but only with a long run up. The back end seems to have stopped shimmying. The last garage at least had the decency to hand her back and say "We have no idea what the problem is.".
So Portland Tacoma-owners. Does anyone have any idea what I should do next?

 

Plugged catalytic converter?

 

I pulled the entire exhaust system and scoped it. There's no sign of a restriction and the vehicle doesn't run any differently with/without the exhaust.

 

what are your compression readings?

its the first thing any responsable garage checks so you should have compression readings from 4 separate garages to compare and see what they are and if they are all the same

and you need to tell us the whole story here from as far back as the engine was running fine, when did this supercharger get installed and was it running fine before that was added?

adding "performance" mods can often cause engine failures on high mileage engines, I have seen many engines crap out after SC and turbo mods are added

 

Does the ecu need to be flashed after supercharger install like the 2nd gen does?

 

With the engine idling tap the MAF lightly with the handle of a screw driver; if the idle fluctuates the MAF is bad (or so I hear- but I should be corrected in 3,2,1....)

 

Could be tens of things based on your information. Please try to be much more specific with the symptoms and describe in detail the conditions/situations they are occurring during.