My 97 toyota 4-runner has now had three times with a loss of power making me unable to drive the car. The first time behaved differently than the last two times. Currently, I can’t drive the car.
The first time, I had just filled up the gas tank (while the station underground tank was being filled). About 10-15 minutes later while on the interstate, I had a sudden loss of power and the vehicle eventually would not move forward at all. The idle was fine. I had it towed to my mechanic thinking I had gotten a back tank of gas. I believe the check engine light was on… he determined that it was a bad mass air flow sensor and replaced that. He said the filling of the tank was co-incidental.
Months later (Jan. 2015), during our first cold spell, I had driven the car, parked it overnight in temperatures of 9 degrees. The next morning it didn’t want to start. I finally got it to idle to warm up in neutral, but then when I would give it gas to move it, it would stall. I finally got it to stay on and to move with barely enough power to drive it the mile to the mechanics. On the way it started “back-firing” under the hood and smelling progressively hotter although the engine heat light was normal. By the time I got it to the mechanic going about 5-10 mph, I thought it was going to catch fire, it smelled so bad. Check engine light never came on. The car sat there unmoved for two weeks while I was out of town. After the two weeks, the mechanic finally checked out the car (outside temp was now up in the 30’s & 40’s) he got it to start and drive, but it was “running rough”. He cleaned up the connections on the coil, which had some corrosion and gave me back the car – no charge.
It ran fine until yesterday, when the same scenario played out. Another cold snap (-4 degrees). Drove the car across town to do errands and fill the gas tank. parked it overnight. The next morning I couldn’t get to start initially. Finally got it to idle. Warmed it up for 30 minutes but it would not stay running if I took it out of neutral and gave it any gas. Check engine light did not come on. This time the car is 30 miles away from my mechanic and I don’t want to have it towed if I don’t have to…
Any ideas? My mechanic thinks it’s either a fuel or oxygen issue. He told me to have someone bang on the bottom of the fuel tanks while I try to start it to see if that effects anything.
Find a new mechanic
This guy doesn’t seem to know how to perform a proper diagnosis. it sounds like he doesn’t know where to start
At least he didn’t charge you
Start by jacking up the wheels one by one and trying to spin them by hand. You may have a brake or two locked up. Especially if you use your parking brakes.
Also, and once that’s addressed, have the ECU scanned for stored fault codes. Post them here.
As regards the fuel pump, which he’s hoping will be confirmed by banging on the tank, you may want to try turning the key to ON a few times for three or four seconds each time before turning it to START. If the fuel line is draining back, that’ll give the pump a chance to refill and repressurize the line before you try to start the engine. If this solves the starting problem, the mechanic would be wise to actually test the fuel pump. That’s done under the hood with a T fitting on the fuel line and a pressure gage.
Be sure the truck has fresh tuneup parts too. Old plugs and/or old ignition parts (like rotors, wires, and distributor caps) cause more starting problems than any other things.
Post back with the results. There are other places we can go, like the temp sensor, but I’m betting your problems will be solved via these actions.
Oh, and I agree with db; find a new mechanic.
Is there any way to leave the parking brake off while you have the problem. Could be sticking. Sounds like a fuel pump, pre pressurizing the the fuel rail would help prove or disprove that. swapping the coil would help.
If you can get it to the shop at the time it is doing this, they can check the OBD II diagnostics, check for proper spark and ignition timing, check the fuel pressure, and check the intake manifold vacuum. That’s the best path forward probably. With the symptoms you are describing, esp the backfiring, and extremely low power, something must be quite a bit off among those.
Often a car that runs like absolute garbage with the pedal on the floor and no top speed to speak of has an issue with the fuel pressure or clogged catalytic converters.
Seeing as how this very poor running seems to be an on or off thing I would think that a fuel pressure test should be run as a first step. I will add that fuel pumps can be intermittent in failure even though many times the perception is that they just go bad and stay bad.
Does this thing still have the original fuel pump in it and when (or even if and how often) has the fuel filter been changed?
When my 70’s VW Rabbit had this symptom it would always turn out to be a fuel problem.
Like some others stated already my first thought is perhaps the fuel pressure regulator is not regulating the fuel like it should be and it is over pressured. That would cause the burning smell from the CAT you mentioned in the beginning. Perhaps a faulty O2 sensor or throttle position sensor may do that also. Another possibility could be the coolant temp sensor for the ECU is faulty and showing that the engine temp is cold even through it is at normal operating temperature. That sensor is usually separate from the sensor used for dash gauge.
Check the EGR system too. When they stick open, this can be the result.