I have just purchased a 98 4runner with 113,00 miles. It has the TRD supercharger and a K&N cold air induction system. It is a manual transmission truck. When I pursue a WOT it coughs and jumps along. If I pursue a throttle slowly it seems to do OK. Also on the highway in cruise mode it will begin to jump at times under a load going up a hill and clear up when the extra load is removed. I have not changed the plugs and the wires are date coded with 1997. I have pulled off the induction tube and throughly cleaned the throttle body. I would appreciate any help. Thanks...
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Choopster

 

i would check out the fuel filter.

 

DOes it have the 7th injector kit.
Very important...

 

is it pinging?

 

if it dosent have any fuel upgrades like the recommeneded trd 7th injector kit or the urd kit then you should pull that s/c off, or get some fuel upgrades.

first things i would check is all the easy stuff. filters, hoses, plugs. all maintenance stuff that should have been done. with that mileage there is alot of maintenance that your truck might have missed out on.

 

Yeah, if it doesn't have fuel upgrades it should really need them. Take a look at urdusa.com.

 

As some guys have mentioned or alluded to already, you are running WAY lean without fuel mods. Those are classic fuel starvation symptoms. They could also be, as was pointed out, simple overlooked maintenance items.

First, pull that K&N and sell it. It's only amplifying an already huge problem. Second, if you aren't prepared to shell out $1000+ and spend some time tuning with a laptop, pull the charger off and sell it. You could get $1000+ for it as is.

 

Thanks guys. I am not sure if it has a modified fuel system but I will replace the plugs, wires, pvc, and fuel filter. What is an easy way to determine what possible fuel mods that may have been done? Thanks...

 

One of the most important items is the fuel pump. If it was replaced with the standard upgrade Walbro 190, you will hear it hum when the fuel gets low at idle. Another way to tell is to shine a flashlight on the injectors and see if they have a colored top, such as brown, red, or whatever. And last but not least, you can pull the glove compartment hatch off, remove the HVAC piece, and see if someone has hacked in to the wiring for the ECU. Hacking the ECU wiring is the only way to properly control the fuel trim for larger injectors (to allow a piggyback to run) so that would probably be the easiest check.

Other than that I would just look for the 7th injector, which is mounted on the supercharger casing by the throttle body if I am not mistaken. If you don't have any of these things pull the charger off or get them ASAP. Seriously, this is something not to be messed with. TRD should have never advertised this as a true bolt on kit and they know it. That's why they put countermeasures in place to attempt to alleviate the High Gear/Low RPM ping problem (HG/LR).

The free FMU mod might make things a little better in the meantime as well. Do some reading at www.gadgetonline.com and you'll see what we are all talking about.

 

Thanks very much. I will check this out and let you know my findings. Regards,

 

May want to do the simple things like maybe make sure you are running premium gas which is what the super charger needs for sure, and since you just got it maybe no one told you that yet. Also may want to run a can or so of fuel injector cleaner through to see if maybe that will help too (II use 44K), it does sound like your just starving for fuel so maybe that fuel filter a little clogged.
I am probably one of the few that have not done any fuel mods and I have to say I have not had any problem with my super charger but I also don't go and get on it every chance I get and its been on my truck a few years now.

 

Thanks WT...

 

Hi WT,
I changed plugs, wires, and fuel filter. Proble is gone, thanks very much.