Please Help! Engine Problem

Okay so I have a 2000 toyota tacoma 3.4 liter 4x4. The truck has been getting worse and worse over time about not wanting to have power when I first start it and drive down the road. There is no power when you press the accelerator and it shudders. I replaced the spark plugs, fuel filter, and the catalytic converter was taken off and a straight pipe was put in. NOTHING HAS HELPED

 

o2 sensor, fuel pump maybe?

 

Well I am not thinking fuel pump because the idle is way to good on it and I've talked to a couple of people and they don't think it would be the O2 sensor which it might be.

 

Have you actually checked/replaced the O2 sensor? Also, check the fuel pump. That was part of my truck's problem- also, clean the MAF. It did wonders for my truck.

 

Fuel pump.. fuel filter... if all checks out.. look at the coils and ingitor could be bad.. Cound be a loose ground on the engine also...

CHECK Compression !!!!!!

CEL ON??

 

I don't know if injectors being plugged a bit would do that, diesels at work act like you describe but they always end up with plugged fuel filters.

 

I've seen a few fuel pumps let go and idle fine but not have enough once under load. Getting that tested would be top on my to-do list with what you've already done. You didn't mention but I'm assuming no check engine lights so that's another reason I believe you start here..

 

No I haven't replaced any sensors yet. I wanna make sure thats what it is before I go doing that because they are like $90 a piece.

 

Fuel pump is going out can run a engine at idle but as rpms go UP the pump cant keep up with the pressure needed to keep injectors running smoothly. Only way to test is to put a gauge on it to confirm pressure..

 

Check engine light has been on but it isn't right now. It was giving a reading of the motor being to lean.

 

Lean bank problem?

 

I don't even know I didnt look at the screen the guys at O'reilly's just told me that it was running to lean.

 

check for vacuum leaks first..

clean maf

 

Definitely check your Mass Airflow Sensor. They can get dirty and cause the truck to run lean- my Taco was running lean, (hesitating upon acceleration, fine during idle) and we tried everything- the last thing we did was clean the MAF and throw some good premium gas in the tank- and then the problems disappeared.
MAF is pretty much a heated wire suspended in the intake air stream. Variations in airflow will cause the amperage of the current to vary according to the cooling effects of the air flowing past the wire. The MAF changes that variable value into a frequency value that's sent to the PCM to indicate the grams/second of air flowing into the engine. Dirt/trash/oil residue cover and insulate the wire from the cooling effects of air flow and causes it to lose sensitivity to changes in air speed and density. There's a certain ratio of air to fuel, and if the MAF can't get a right reading, then you end up with more air in the mixture than it registers, causing a lean fuel ratio.
If you go to clean it, use MAF sensor cleaner- if you use anything else, you run the risk of messing with the sensor's sensitivity.

 

Okay I will check the AFS tomorrow!

 

Let us know how that goes. Hope it does it!

 

Okay guys I forgot to mention yesterday I also had my alternator checked on the truck and it said it was a little weak. Then I brought it home changed the fuel filter and it ran great. I then changed out the end of my positive battery cable and put it back on. It then seemed my battery was dead so I put another one on it. I hooked it up and it crank right up but once again it was doing the same thing with no power when your pressed the accelerator. So could the alternator being bad have anything to do with it?

 

If the battery is weak/low charged and the alternator is not putting out, then yes, your performance could be affected:

Ignition power (i.e. spark) is based on the primary voltage peak before break-over. For example if the average primary voltage is 13 volts and you have a 4000:1 secondary output, then your secondary voltage would be 5200 volts. This results in a good, strong spark. But if your voltage gets too low, perhaps as low as 8 volts, then your secondary voltage would drop to 3200 volts. This would severely affect performance. Also this low voltage reduces a fuel pumps output by as much as 40%. Obviously that much output loss can result in performance issues as well.

I am not of course saying that is what is wrong with your truck. I am simply answering your question on if a bad alternator could cause performance problems. If you think you have alternator issues, take care of them BEFORE you try to do ANY other diagnosis. Low voltage can cause sensor codes as well as other erratic behavior. You must have a steady baseline before you can even think of doing a proper diagnosis.

 

Thanks BamaToy1997!

 

It does have a good strong battery now and is still doing the same thing. What does that tell me?