'99 4Runner running bad....

[chcpnoman]

Just acquired our first 4Runner and am encountering driveability problems already (on the way home from the dealer!) Sometimes it idles fine, and will accelerate nicely through the gears (5 spd), and other times the idle will become erratic - sometimes stalling, and there is loss of power in acceleration, spewing black smoke, sometimes bucking, and obviously awful gas mileage. Dealer sent me new ECM, which I already changed out, and the problem is still there. Checked the archives for similar problems, and am interested in the current collective wisdom from the tribe. Fuel problem, electrical problem.....?

Meanwhile the truck sits in the driveway awaiting a cure. Help?

Thanks in advance,

chcpnoman

 

[Iowa4Runner]

Is the check engine light on? Has anyone checked it for OBDII trouble codes? If the computer says everything is normal then it's time to check basic maintenance stuff. If it looks like it's been neglected check for a plugged fuel filter, dirty air filter, fouled spark plugs etc. It that's all fine then I'm not sure what to tell you. How many miles are on it?

 

[chcpnoman]

Thanks, Iowa4Runner,
Yes, the "Check Engine" light is on all the time. No, it has not been scanned yet for codes. Have an appt. for Monday for that, but am hoping to go there armed with some background....
Truck has only 53K miles, and could have been neglected by previous owner(s). Wondering if it's not an electrical problem somewhere (relay, short, bad computer,etc.) maybe it's fuel related (filter-too easy, injectors=$$)?

 

[Iowa4Runner]

Well the good news is that Toyotas are built pretty well and sometimes the simplest problems can cause some pretty frightening symptoms. For example, my parents' had a 1990 Mercury Sable that behaved similarly to what you describe and the only thing wrong with it was that the coolant level was too low. The computer sensed this and was running in some kind of "limp home" mode which ran the engine super rich with no ignition advance to help keep it from overheating. Your 4Runner woes might be cured by simply replacing an intermittent coolant sensor. That's just one possibility of many, but I'd be surprised if it took a major repair to get your 4Runner back in tip top shape. Let us know how everything turns out...

 

[chcpnoman]

Throwing this topic up here again, in case anyone else can offer some ideas over the weekend. Anyone else had problems similar to this?
Thanks in advance.

 

[ilocan]

You may want to try cleaning your MAF sensor. The MAF is most likely the number one culprit of any 3.4 motor. Also disconnect your battery for a few minutes to clear out the check engine light codes.

 

[03RoadRunner]

Some helpful hints???

What Ilocan said and you may want to check these things:

1) Air Filter and maybe remove air intake (very easy) and check the throttle intake for carbon buildup..if dirty clean with throttle body intake cleaner from local Autozone or Auto Parts store.

2) Check all your spark plugs while you have the air intake off. I just replaced mine after 100,000 miles on my 1998 SR5V6. I was having similar problems you listed above.

3) The fuel filter may need to be replaced (every 30,000 or so miles). I just changed mine at 95,000 miles...opps. I got some awesome throttle response back!!!

4) Change Oil and filter?

5) Check engine light is usually just an emissions thing I believe. You can run your vehicle while the check engine light is on..you just won't pass inspection maybe. Although SUV's are allowed to have outrageous emissions...the emissions on these things have a huge margin compared to a normal passenger vehicle.

6) Take it to dealer and run codes on it. Don't you have like a 90day warranty on a used car? Did they include at least a 30day warranty?

Take care...and good luck man!!!

03RR

 

[chcpnoman]

Preliminary follow-up:

Initial consultation with repair shop today yielded:
1)O2 sensor bad
2)Underdash wiring harness not original, and not the right one for this truck! Carfax showed no accidents reported, but somewhere along the line somebody fooled with the wiring for some reason, which is also a culprit for many other problems (from a/c to airbag to horn to cruise control). What a mess to straighten out now.

Thanks for your help guys. Will let you know how things turn out from here. Am really looking forward to using our "new" truck when we get it going good again.

chcpnoman

 

[Iowa4Runner]

Preliminary follow-up:

Initial consultation with repair shop today yielded:
1)O2 sensor bad
2)Underdash wiring harness not original, and not the right one for this truck! Carfax showed no accidents reported, but somewhere along the line somebody fooled with the wiring for some reason, which is also a culprit for many other problems (from a/c to airbag to horn to cruise control). What a mess to straighten out now.

Wrong underdash wiring harness??? Holy cow who would have guessed that one? Maybe someone's car stereo project got out of hand. Tell me you're not getting stuck with paying the repair cost...

 

[whomhead]

Carfax is a joke. I asked for a carfax report before we bought our '99 limited. He printed it out and handed it to me while we were signing paper work. It came back clean. The next day my dad and I were crawling around underneath the thing and most of the front end parts had been replaced seven months ago. Through my research about carfax I found out that dealerships or insurance companies are only required to report to carfax if it's a total loss. So buyer beware, carfax isn't what it's cracked up to be.

 

[yellow1342]

FYI info from msn auto

some occational problem on 99 t4rs

An occasional problem on this vehicle is failure of the Mass Air Flow (MAF) Sensor. Failure of the MAF Sensor can cause a drivability problem or the check engine light to illuminate. On some vehicles, the MAF Sensor can be cleaned and will not need to be replaced. The cost to replace the MAF Sensor is estimated at $148.90 for parts and $58.50 for labor. All prices are estimates based on $65 per flat rate hour and do not include diagnostic time or any applicable sales tax.

link:
http://autos.msn.com/research/vip/reliability.aspx?modelid=2834

good luck hope is not too late!: