1998 Frontier 2.4L 4Cyl UNDERPOWERED?

[gfaris]

Hi All! I just bought a 1998 Frontier manual 4x4 with 2.4L 4 cylinder. When I test drove it it felt a bit under powered but seemed to work well. I didn't get it over 50 though since the truck had no license plate and I couldn't go on a highway. When I took it home it won't go over 70 on the highway. It works well with ok power until about 60, then it gets really slow and simply won't go over 70. Is this just an underpowered engine and this is normal or could something be wrong with the car? If so any idea what the problem would be? Thanks a lot for reading.

[AZhitman]

The KA24DE is a great engine, so I'm guessing that one has some issues.

My '99 Frontier would do upwards of 90 without issues.

I'd say your first task would be to do a complete tuneup - Does the truck have a Check Engine light? How many miles? Any modifications? Stock tire size?

Once we know all that, we can start walking you through some of the maintenance items. We've even got a factory service manual for your truck!

[gfaris]

Thanks hitman, I appreciate the quick response. I should have been more careful and took it on the highway, regretting it now but I only paid $3500 so it was fairly cheap and in overall really good shape other than this speed thing. I'll try a tune up on it, plugs and wires to start. In answer to your queries, no check engine light is on and the miles are 140K. I don't think there's any mods at all, most of the parts under the hood appear to have roughly the same amount of age to them. One notable thing though is the tires, they're new "31x10.50r15c1 BF Goodrich mud-terrain T/A KM2" tires (according to the sales receipt). They're definitely larger than stock. I just drove it around some more and it has totally acceptable power less than 30 and 30-50 seems pretty good too. I wonder if it could be something as simple as the wire linkage on the gas pedal not giving it anymore gas past a certain distance pressed.

[BRubble]

Hi All! I just bought a 1998 Frontier manual 4x4 with 2.4L 4 cylinder. When I test drove it it felt a bit under powered but seemed to work well. I didn't get it over 50 though since the truck had no license plate and I couldn't go on a highway. When I took it home it won't go over 70 on the highway. It works well with ok power until about 60, then it gets really slow and simply won't go over 70. Is this just an underpowered engine and this is normal or could something be wrong with the car? If so any idea what the problem would be? Thanks a lot for reading.

Is it in 2wd or 4wd doing this Speed Test?

[gfaris]

Hi Barney. It's in 2WD while doing this. I tested the 4WD on a dirt road and both high and low seemed to work as they should.

[BRubble]

Hi Barney. It's in 2WD while doing this. I tested the 4WD on a dirt road and both high and low seemed to work as they should.

If it were mine, I check out any trouble code's and or light's. Then I would start doing a thorough routine maintenance check of everything, ie Air Filter/Crank Case Filter, Fuel filter, plug's, Engine Oil, Rear Axle Oil, Transmission Oil.

I've replaced an oxygen sensor in the 93 hardbody with the 2.4L engine, and I don't remember why. Maybe it was called for in the maintenance schedule. Here's the Bad Oxygen symptom's:

http://blog.fcpeuro.com/2014/02/13/diag ... ing-signs/

What you describe seem's like it may be a bad oxygen sensor.

While you're doing the Routine Maintenance be on the lookout like you were saying Throttle Linkage, and anything out of the ordinary.

That's about all I can think of at the moment.

Good luck,, and let us know, how it is going.

[gfaris]

Much appreciated Barney, lots of good things for me to check out. I'll keep you guys updated. If anyone else has any ideas in the meantime or experienced this issue I"d love to hear about it. Thanks!

[gfaris]

I read the oxygen sensor article, and my truck sometimes has a rough idle like mentioned, goes up and down about 1000 RPM sometimes, could be that, would be very nice if so

[Desert Rat]

Is this a flat stretch of road, or is it at all uphill?

Your truck came stock with 235/70/15 tires that were approximately 27.5" tall. You now have a 31x10.50 tire, most of which average about 30.5" tall, so you've increased tire size by about 11%, and that's how far off your speedo is. 70mph on the speedometer is really closer to 78mph. Yes, the KA is underpowered in a 4x4 truck, and with the larger tires with more rolling resistance and greater weight, it's possible that's all she has, especially if the road isn't perfectly flat.

On stock tires when my truck was new it was acceptable. I went to 31s with stock gearing and it takes more power to turn bigger tires, and it slowed down bad on big hills.

I've had min 16 years and am on the second motor. I'm regeared to 5.14:1 from the stock 4.625, and am running 35" rubber on a solid frot axle with a few hundred pounds of extra offroad armor. You think your truck is slow.......ha!

Do what Hitman said. Give it a good ignition tuneup, and consider opening up the exhaust to 2.25". A cold air intake will help marginally as well.

[gfaris]

Thanks desert rat, your post made me feel quite a bit better. I'm in Florida so there is very minimal hills, though in my part there are some slight grades. I'm glad the speedo is off b/c 78 is way better than 70 to me, I don't drive much more than 75 typically anyway lol. I'll give her the tune up as suggested and look into the gearing and exhaust, great ideas.

[BRubble]

I read the oxygen sensor article, and my truck sometimes has a rough idle like mentioned, goes up and down about 1000 RPM sometimes, could be that, would be very nice if so

A partially clogged exhaust, can also cause the symptom's as you are haveing as well:

http://www.freeasestudyguides.com/catal ... st-a8.html

There are several way's to check, if the Catalytic Converter is causeing an exhaust restriction.

My '93 was 2wd AT 2.4L, and that thing would easily go over 90 mph. I never tried to see how fast it would go,, but no problem accelerating above 70 mph at all. The 4WD I guess may be a lot different though. I never drove one of the 2.4 4WD's.

Good Luck

[AZhitman]

ALL great advice. The KA loves to breathe, so if you can open up the exhaust a bit, you'll love the improvement. I think I had a JBA exhaust on mine... the other guys can chime in on others.

Adding an intake won't hurt (a cheap one should be fine). If your cat is original, it's not a big deal to replace it. In fact, let me know if you go that route, I can hook you up with a high-flow Magnaflow unit through my shop pretty cheaply.

Tune up, fresh plugs and wires, all fluids changed, make sure the brakes aren't dragging, clean the MAF, clear out any unnecessary weight, and one more thing to replace: temp sensor (they go bad, and can cause drivability issues).

Glad to have you aboard - How about some pics of the new beastie?