so SLOW

[Jason94sport]

Is it the gearing? Power band of the SOHC? Emissions junk? 5MT gearing? All of the above? This thing goes no where fast. Compared to my 1st gens it's a dog. 2nd gear especially. I've driven the auto's & they don't suffer from this.
It's a real PITA when I'm tying to merge into traffic or I make a turn & have to get on it to avoid the idiots driving too fast. I also have to drive in 4th all day because when I try to pass anyone or accelerate in 5th it takes too long.
I understand it's slow, not a speed machine, but it's actually very annoying to drive.

 

[Mbrooks420]

It should be a lot peppier than the OHVs in the first gens. I’d say your issue is gearing, or there’s something wrong with your SOHC.

What’s your gearing?

 

[ziggins]

Maybe your cat is plugged?

 

[Jason94sport]

3.73. Don't think there's anything wrong with it. No codes, runs ok otherwise, no noises, sputtering bad idle nothing like that.

 

[Mbrooks420]

That’s not what I’d expect. It’s got about 40 more hp and a little more torque. It probably happens later, though. Are you just not winding it out enough?

I still think something is off if you are having trouble pulling 5th.

 

[ziggins]

My Dodge didn't throw codes, it lost power the warmer it got.

 

[donalds]

Check the cat pressure forward and aft

 

[RandomNerd2000]

Check the exhaust backpressure before the cat, something is definitely off if you can't pull 5th.

 

[Jason94sport]

It moves well past 65. Does 80 just fine. I'm shifting around 3K RPM, Maybe that's too low? I feel like I have to go to 5K to actually pull lower gears. It's a lack of throttle response as well. It's just slow to move, I mash the gas at 2500RPM in 2nd, everything moves, but doesn't seem till I hit 4K or higher that I get any decent acceleration.
My 1st gens all had BBK TB's. Maybe that's the difference I'm feeling?
The exhaust didn't do much. it was like it before & after. I also put on a cone filter & dumped the airbox as a test, & again didn't do much.(back to stock now)

 

[RandomNerd2000]

Out of sheer interest, you done a fuel filter on it? Plugs and wires?

 

[974X4BLACKSPORT]

DO a cranking compression test, this will give you a good idea of the mechanical "health" of the engine. A healthy street engine should have between 150-180 psi while cranking, and all be within ten percent of each other, a weak engine is going to have low (140 psi or lower) and inconsistent numbers. High mileage worn rings and cylinder bores leak and create blow-by that you wont even know about unless you look for it.

 

[Jason94sport]

Fuel pump was replaced before I bought it along with the fuel filter I put plugs & wires in after I bought it.(10 months ago) Only 96K miles.
I'll have to find someone to do the tests. I no longer have room or tools for most things.
I'm sure the 80-90 with 90% humidity & the AC always on doesn't help things though.

 

[donalds]

Check the cat pressure forward and aft

Check the exhaust backpressure before the cat, something is definitely off if you can't pull 5th.

I think we are on the same page

 

[Mbrooks420]

Am I correct in thinking the computer would have no idea if the rear cats weren’t functioning since there’s no O2 feedback?

 

[RandomNerd2000]

I had an Explorer with no cats on it, it performed just fine, didn't do what he's describing. Anybody checked the O2s for functionality though? Watched the live data on a scan tool?

 

[Mbrooks420]

I think the suspected issue here is clogged cats which would be entirely opposite of having none...

 

[Jason94sport]

Actually I have the scanner & forscan... I'll have to check it out when i get time.

 

[CDW6212R]

The SOHC 4.0 should run to 5500rpm to shift for each gear, below 2500 it's not that inspiring. I don't know what the manual ratios are, but the 5R55E has good close gears to make it move once off the line. My 302 is much quicker to start out, but the SOHC will keep up with it at WOT above low speeds like 20mph.

My 99 SOHC Explorer is 4WD, the 4.10 gears do help.

I'd test the fuel pressure, be sure you have 62psi minimum all the time. If you know the tune up items are good(plugs/wires/filters), then look at the exhaust back pressure ahead of the cats, and lastly a flasher/tuner to correct the A/F ratio for any modifications. You should be around 200rwhp with a good condition engine etc, and it should be much faster than the old OHV 4.0's. I've owned two of those also, they sound like they are trying hard, but the SOHC is much quicker after 20mph.

 

[J_C]

Mine ('98 4.0L SOHC) was slow when it had been sitting for a long time and the battery was low. I'm guessing it was a weak spark from combination of old plugs, old wires, which I replaced, and soon after I replaced the alternator, and the battery had been weak for a couple years, finally replaced that too.

At the time I noticed it ran MUCH better if I'd been driving it for several miles, then started it back up a few hours later (was long enough to be fully cold again, because winter) opposed to how it ran for the first 10 minutes after sitting for days. I mean it had done that even before winter set in so it wasn't especially cold outside either, not a thick oil issue.

Even so, mine with 3.73 gearing seldom sees engine RPMs above 3200-3500ish, doesn't need higher.

 

[koda2000]

My POS '01 ST 4.0L SOHC Job 2 is pretty damn quick all things considered. It has 4:10's, which I think must make a huge difference. Our old '97 SOHC Sport was slow by comparison. It had 3:73's.