Engine gives around 3500rmp?

[97PickUp]

I have a 1997 Nissan D21 Hardbody with a 2.4L engine. When I am trying to get up to speed, the engine will basically give out from 3500-4100rmp then catch back up. Its like a..sluggish feeling. I replaced the cat. and that helped a little bit, but there is still an obvious slow down to the engine. What do you think could be wrong with it? Thanks!

[Desert Rat]

Any codes?

As a general rule, I'd replace the O2 sensors and clean the mass airflow sensor

[seang]

Modified by seang at 3:10 PM 7/9/2009
Modified by seang at 3:11 PM 7/9/2009

[Rev_D21]

Speaking with a Nissan friend of mine he said the 96-97 trucks were dogs when Nissan made the switch to ODBII with 97 being the worst of the two. This is compared to the older models, pre-ODBII.

[seang]

Some engines do have a midrange flat spot in the power/torque curve. I wasn't sure how 97PickUp meant his question, it sounded like the engine cut right out. I notice a flat spot around that rpm, but when I need to accelerate into traffic, I will always run from 4400-6200 rpm's, intermittantly of course. The peak torque for the ka24e comes in at 152 lb ft 4400 rpm, and peak power at 134 hp 5200 rpm. redline 6000 rpm. I don't race it hardcore, because I don't actually get paid to thrash it that hard, but I do let it rip. Some people scoff at the 134 hp, but it is a well performing 134 hp.
Modified by seang at 8:51 PM 7/1/2009

[RT22]

Most power is made before 3500 anyway, why rev it so high? I have never exceded 3000 or so as it just makes more noise not much more power.

[C-Kwik]

First thing I would do is check for codes as DR mentioned. Could save you a lot of poking around if it narrows down where the problem seems to be.

Next thing I would check is the spark plugs. Confirm they are not worn out and look for signs of troubled combustion or an ailing motor.

Next, I would throw in a can of seafoam in the gas tank just before you fill the tank. If the injectors are dirty, it can help clean them out.

While I wouldn't necessarily jump on replacing O2 sensors, I wouldn't rule it out. They are wear items and will need replacing to maintina optimal performance as they are part of the closed loop feedback cycle that helps to make sure the amount of fuel being injected is accurate.

[97PickUp]

The engine "boggs" out around 3500rmp. The engine hasn't thrown ANY codes. It only has this problem in gear, I can rev it up all the way idling with no problem.

[NM50]

It actually sounds like a bad throttle position sensor.Check the wires under the air cleaner housing as they tend to rub through.And there is a maf in the KA24 IN 97.It is in the throttle body.

[97PickUp]

Thank you!!!! You saved me so much time and money.

[97PickUp]

Thanks for your input everyone! I cleaned the mass airflow sensor and that did the trick...for now!When i originally bought the truck the owner said he replaced the first of TWO O2 sensors - i'll replace those when i get a few extra bucks. Anyone had trouble installing universal sensors? or should i just get the ones made for the truck?

[97PickUp]

I tried this - it felt really really good for the first few miles - then basically dogged on me.