# Spotty Power and problems at higher rpms



## cjserio (Mar 18, 2008)

I have a 1994 4 Cylinder 4x4 Pickup. The truck has 167,000 miles on it but it's a new truck to me. I'm noticing that the power curve is very very spotty on mine. It seems like if i try to accelerate too fast it loses power but eventually gains it back a few hundred RPM later...It feels like something's holding me back in spots. Also, in 1st and 2nd gear, when i get to around 3,000 RPM, I feel like i lose a large amount of acceleration and power.

I realize it's only 106hp and i'm not expecting a hot rod but it just doesn't feel like the engine's running properly. What do you think could be the problem? It idles fine at around 1,000 rpm, in neutral it revs smoothly throughout the range. The parking brake is not stuck or frozen. Any ideas?


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## cjserio (Mar 18, 2008)

I forgot to mention that the air cleaner is practically new and free from dust/debris.


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## rdixiemiller (Mar 6, 2008)

Fuel filter OK? Plugs good? Timing correct? Could be any one of a number of things. Restricted exhaust?
I'd look at the obvious things. Fuel filter would be first. Not sure on your truck, but many vehicles have a sock filter in the tank on the pickup tube. When it starts to plug up you will see loss of power at higher rpm, eventually geting to where you can't maintain 45 mph.


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## cjserio (Mar 18, 2008)

Plugs are new, fuel filter is new...Not sure on the timing though...I'll have to have my mechanic check that out.


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## cjserio (Mar 18, 2008)

So just an update...the mechanic checked the timing and it was 1-2 degrees off. He adjusted it and also changed the catalytic converter and fuel filter (again). It's running smoother but it still seems to hit a wall at 3,000RPM. The engine sounds totally different and begins bucking slightly and refuses to rev up very fast. Any other ideas? I've thrown a lot of money at this problem.


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## cjserio (Mar 18, 2008)

So more updates....I cleaned the Mass Airflow sensor and it solved a lot of the performance problem but it's not quite there yet. I also installed new plugs and found that one of the old plugs was in cross threaded and not seated completely (why don't people thread plugs by hand!?!?!). After retracing the threads and getting new plugs in...the truck doesn't perform much different. There are no codes in the ECU and the check engine light is off.

To summarize what problem currently exists, as i accelerate through 3,000 RPM, the engine seems to lose it's ability to rev/accelerate at the same pace. You can audibly hear the tone of the engine change. With my eyes closed i can tell when it hits 3,000RPM. It sounds like there's a vibration above 3k but there's no violent performance drop or misfires....It just seems to get weak. My gas mileage is pretty poor as well. I think i'm getting about 15mpg city. I'm very lucky if i can squeeze 200 miles out of a tank of gas. What else can I do?

Here's what i've done so far:

Cleaned Airfilter
Cleaned MAF
New Plugs
New Fuel filter
Adjusted timing
New Catalytic converter
Checked TPS
Checked Ignition Coil resistance...Seems fine to me
Checked vacuum hoses...also sprayed with Carb Cleaner...no noticeable difference
Ran 3 Bottles of Fuel Injector cleaner through 3 tanks of gas.


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## cjserio (Mar 18, 2008)

It's been a while...anyone have anything else to add that may fix my performance issue?


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## zanegrey (Dec 5, 2005)

check the aiv for corroision and or damage...


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## Nissanman7166 (Feb 12, 2009)

Could be a worn muffler bearing!!! hehe J/K GL


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## mitsuspyder (Feb 27, 2009)

does the 1990 up pathfinders carry tat sock type filter in the fuel tank tube


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## cjserio (Mar 18, 2008)

mitsuspyder said:


> does the 1990 up pathfinders carry tat sock type filter in the fuel tank tube


I'm not sure. I haven't found any mention of it. The whole car really vibrates at like 3200rpm. I'm not sure if a little fuel starvation would cause that though....It runs smooter above 4k (that is, no more vibration) but still not right.


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## zanegrey (Dec 5, 2005)

yes it does but that is not it..


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## Pynikal (Dec 11, 2008)

Nissanman7166 said:


> Could be a worn muffler bearing!!! hehe J/K GL


post whore. keep it relevant....

back to topic.


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## cjserio (Mar 18, 2008)

zanegrey said:


> yes it does but that is not it..


Well i found a 6" round flat disc shaped like a tin of turtle wax...I opened it up and only found a little filter. Filter looked okay and so did the tin...From what i read, this is the AIV filter....Is that what i'm supposed to check?

I just don't see how this secondary bypass air can be causing crummy performance and a vibration...


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## zanegrey (Dec 5, 2005)

ne thing that is connected to the vacumn can affect engine performance..


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## dvdswanson (Nov 6, 2005)

did you replace the cap and rotor?


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## D21jrc9009 (Sep 29, 2008)

Not to be redundant and useless, but don't the ka24e trucks have 136 horsepower? I thought the z24 engine was the 106 hp


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## cjserio (Mar 18, 2008)

dvdswanson said:


> did you replace the cap and rotor?


No I haven't...I'm pretty sure the original owner did though. How can I tell if it needs replacing?


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## cjserio (Mar 18, 2008)

D21jrc9009 said:


> Not to be redundant and useless, but don't the ka24e trucks have 136 horsepower? I thought the z24 engine was the 106 hp


You may be right....At this point, i think i'd be happy with 106hp....


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## cjserio (Mar 18, 2008)

Well i just checked the cap and rotor. The contact on the rotor seemed a little dirty so i cleaned it up and the contacts on the cap each had a little white dot of corrosion so i sanded it down to clean metal and cleaned it up.

Overall, it looks to be in good condition...the corrosion really wasn't too bad.

It took it for a spin after that and didn't really notice any change....The vibration at 3200rpm is what's really concerning me...Maybe it's normal but it's so hard to accelerate past 3200rpm that it's more noticable.

Does anyone else with a KA24E have trouble revving the engine above 3,000rpm? Do you notice any vibration at 3,200rpm?


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## mitsuspyder (Feb 27, 2009)

well i know that a similar situation happened with my pathfinder, like if the cap isnt on properly it a release out some of the pressure out of the tank so it affects the rev so if u like for example open the acceraltor up it seems to shutter off and there is no power in the low to mid rpm range.


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## CMax03 (Jan 17, 2009)

Sounds like an air intake leak or a defective EGR system component!


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## Nissanman7166 (Feb 12, 2009)

Are you sure the vibration is coming from the engine???

When I got my truck the U-joints were in bad shape and needed replacing. It would vibrate at around 3000 rpm's and go away at around 3300. of course it only happend when driving.

Just tryin to help


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## cjserio (Mar 18, 2008)

Nissanman7166 said:


> Are you sure the vibration is coming from the engine???
> 
> When I got my truck the U-joints were in bad shape and needed replacing. It would vibrate at around 3000 rpm's and go away at around 3300. of course it only happend when driving.
> 
> Just tryin to help


You're talking about the U-joints on the drive shaft? That would be speed dependent not RPM dependent. It doesn't matter what speed i drive, I lose power and gain vibration at 3,200rpm. It's not a violent vibration, it's more of a loud hum.


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## smikster (Aug 12, 2008)

*seafoam love...search it...just seafoam not love*

go ahead and replace the egr can't hurt only like what 5 bucks?

if you haven't flushed your engine be sure to do that. 

and if that truck has never seen seafoam...omg...poor poor thing...

give it a good smoke love....every 25-60k miles

when i got my truck on the way home i stopped to do one...hardly ran. went from dumping the clutch in 1st pedal to the medal and umm nothing to dump in 2nd and smooookkkeeee on the tires dum dum dum..dum dum dum dum...(smoke on the water)


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