Losing power while driving

Guys I'm new here and need major help.. I have a 1996 toyota 4 runner 3.4 auto and driving down the road it just loses power and start spitting and stuff. You can give it more gas and it will clear up until you take your foot of the gas and then re apply the gas and it starts it again. I have hooked it up to a computer and says the idle air control .. Could this be my problem?? Any advise will be greatly appreciated

 

Long ago I had a '86. Completey different motor, however, it was acting very similar. Turns out, it was the TPS, (Throttle Position Sensor) combined with a bad O2 Sensor...just a thought.

 

I have been told the tps I have changed the whole throttle body with a different tps and iac now it's hesitates to take off from stop or climbing a hill

 

Fuel pump?...vacume leak?

 

I was thinking fuel pump just wanting other input on it honestly.

 

Unfortunately, you don't know until you replace it. Maybe a Mechanic knows of a test though. Don't think it would show up on a diagnostic....?

 

It hasn't showed anything fuel related other that fuel bank one and two lean

 

Fuel pump weak or getting too warm, TPS dirty inside?
Easy to check. You can pull the TPS off the throttle body and LOOK at it for corrosion, or put an multimeter on it, in Ohms mode, and slowly open the throttle plate all the way. Watch the readings on the multimeter. A dial version is easiest to monitor, but digital ones will work too. As long as the wipers are on the slides they ride on, there should be a smooth change in value. No sudden jumps to open or shorted.
The TPS is also known to get dirt inside, and as the dirt and corrosion build up, it can interfere with the smooth change of values. Really annoys the ECU, not to mention the owner

The O2 sensor(s) are know to only last for so long, then require changing. I can't find where I read it now, but I thought I saw someplace they're only good for 60,000 miles or so. That was on the 87's I have, but it should be similar.
If you have the O2 sensor(s) with the shield covering the wire coming out of it...a wire braid over the actual conductor, it's been known to break at it's end away from the sensor, and needs to be soldered back down properly. Otherwise, it causes the information from the O2 senor to the ECU to appear bad to the ECU.

Good luck!
Pat☺

 

Thank you pat what about it being sluggish climbing a hill and at take off?

 

Did you use a NEW throttle body or a used one?

A used one is going to have the same issues. That is also going to cause problems at take off.

Get a new TPS.

 

Clean the MAF

 

Spark plugs, wires, cap and rotor?

 

Cap and rotor? Don't think a 96 is quite that old school.

 

A bad fuel injector?

 

3rd gen guys awesome!

Glad to see the new guy getting some help…

 

Is there a way to test fuel injector ??

 

Unless you are getting misfire codes, I wouldn't focus on a bad injector first.

Can you give us the exact code or codes you got?

I still suspect you have a bad TPS. There are typically two spots a TPS goes bad...one is where you are just maintaining speed with the gas pedal (sounds like the problem before you replaced the throttle body) and the other is at idle at a stop (sounds like the problem after you replaced the throttle body). The reason, is that's where 90% of your pedal is over the life of the car.

Other things that can affect driveability like this are a dirty Throttle Body, a dirty MAF, bad plugs, wires, etc. But because you changed the TB and the problem changed...I'd focus on that area.

If it were me, I'd swap just the old TPS on, should take a few minutes, and see if things change yet again. If the problem remains the same, then it may be something else.

 

It stopped jumping and smell of fuel when I changed the whole throttle body but now it's sluggish at take off and climbing hill the check engine light just came back in today I'm going to put it back on the computer in the morning I really appreciate all the input.. I'm dumb as they come doing this stuff

 

Yeah, post us the code(s) when you get it.

You may have 2 issues.

Hesitation from a start just reeks of a bad TPS.

Sluggishness when trying to accelerate, or loss of power above a certain RPM reeks of a bad fuel pump.

 

Rereading your description, is the problem at takeoff a "hesitation" (put foot down and nothing happens for a bit but engine eventually takes off)?

Or does the engine want to go initially, but can't increase power and bogs down?

If it's truly acting sluggish moving from a stop, and up a hill, it may be fuel related. Which points to bad fuel pump and injectors.

Here is a good video on fuel injector diagnosis:
https://www.youtube.com/watch?v=XhYEDkpF3Qs

 

I definitely think this problem has been narrowed down at least.

 

Has been narrowed down a lot and like I said before I really appreciate it guys. It's hesitant to gain speed and climbing hill I'll post codes tomorrow

 

Went put it on the scanner again saying bank one of sensor lean and bank one o2 sensor bad?? Could o2 sensors make it drive like it is

 

Yup.

 

lol, IDK, dont have a third gen. So a 96 4runner doesnt have an ignition cap and rotor? Does it have a coil pack?

I had wires, cap/rotor on the ignition system of my 1999 v-tec (yo!). I replaced it twice in my 20 years of ownership. So I figured a third gen 4runner that was even older might still have the old-school ignition system.

 

Your 4Runner does not have a distributor cap and rotor. It has coil packs.

 

Man Im surprised the early 4runners were running coil packs. They have drive by wire throttle too dont they?

 

I got a hesitation, checked the plugs and one was missing prongs. I switched to these four prong eco plugs, don’t do it. Use factory stuff. Three coil packs fire two opposing cylinders only three plug wires cause the coils plug right on. Genius really. Ya it’s all distributerless 96 first year on the next generation.

 

I got a missfire code for bad injector. Just read the codes and tune up. Replace O2’s.

 

If you mean there's a wire cable between the gas pedal and the throttle body, yes. If you mean that it's all electronically controlled, with no direct, physical, connection between the gas pedal and TB then no.
You move the gas pedal, it moves the butterfly valve in the throttle body. Just like the hot water control valve. Wire inside a sheath type cable.

Toyota takes small steps forward in their tech. And they stick with what works. It's a good system, IMHO.

Have fun, all!
Pat☺