Can't get above 2500 rpm...Solved!!

Recently purchased a 1999 Tacoma TRD 2wd 5vz. 220k miles
It drives around town great, on the interstate it is great. But, I have no passing power and I lose speed on steep inclines. Can't seem to get above 2500 rpm. No CEL or codes

What I have done over the past 2 weeks:
New spark plugs (NKG)
New vacuum lines (not all, but a lot)
New fuel filter
New catalytic converter
New thermostat (old one was stuck open)
Oil change
Drive shaft center bearing

Thoughts on the lack of power?

Solution: The timing belt had jumped a few teeth. New water pump and timing belt with proper timing.

 

Unfortunately its a pain to diagnose.

You need to check fuel pressure, which is difficult because it needs to be a threaded fuel line style. (cant suggest any off the top of my head)

Next the MAF is a suspect for sure, you typically measure the current or watch the current on a scan tool.

Last a vacuum check is a good idea to eliminate anything in the exhaust. (new doesnt mean good)

https://www.youtube.com/watch?v=d-jp1IIJVVk

 

Can you rev it above 2500 in neutral? If so, I'd consider compression check.

 

Pull the battery terminal for 10s and observe changes

 

If you can't rev pass 2500 in Neutral it could be cam or crankshaft sensors

 

Today I checked the MAF sensor and cleaned it. It appears to be ok.
I will check compression, vacuum, and fuel pressure this weekend when I can get out to my BIL's house (mechanic).
Will follow up with results.

Thanks for all the suggestions

 

Today I circled back around to the MAF. I pulled it all the way out and gave it a full cleaning with MAF cleaner. After cleaning, I am still averaging 6.5-7 g/sec at idle. I believe that I should be around 3.4-4 g/sec.
Also, I am able to get up to 4000rpm when I turn off O/D.
With O/D on i can hit 2600 rpm with a MAF of 55 g/sec
With O/D off at 4000 rpm the MAF is about 70 g/sec

I am questioning my MAF sensor now...Thoughts?

 

Man, I hate just tossing parts at an issue

bench test the MAF

I found lots of videos out there
One might be your taco specific

 

^I’ll second this. Similar issues a while back. Fine around town but zero power/revs only 2500-2800 for highway speed. Did the MAF route, etc. changed the crank position sensor. Boom-night and day.

 

Did this happen without getting a CEL?

 

Yes - no CEL. Just no power above 2500-2800. Now revs freely and can actually achieve highway speed if needed.

 

Thanks for the info. Ordered a new cam sensor and crank sensor.
Will report back after install.

 

Best of luck

 

Very interested in result
GL!

 

Success! Can't say if it was the cam sensor or the crank sensor, but I now have full power back.

The downside, I now have a P0505 code Idle Control System Malfunction. Suggestions?

 

https://www.tacomaworld.com/threads... controls,proper throttle valve opening angle.

 

If it was working before maybe just a vacuum leak

 

Pulled the throttle body and did a deep clean on it and the IAC. Reset the ecu and went for a 30 min drive. No Codes
Will follow up in a few days, but it seems that things are good.

 

Ok, while the cam and crank sensor made a noticeable improvement, It turns out that my timing belt had slipped a few teeth.
Just finished water pump and timing belt, and with proper timing, the truck drives amazingly!
Like moving from a 4cyl to a 6cyl.
Thanks for all your help!