I'll be going a steady MPH and then i'll need to speed up and pass someone or go up a hill or something so I push the gas down...nothign happens...down a little more...nothing happens. I finally mash the pedal down a second later the RPM's fly up to about 3200-3300 and I speed up.

Anyone have really slow accel on their six? I have about 78k miles on mine.

Has anyone been able to get there six above 3200-3300 rpm? Even I floor and leave it down once the tach hits the above RPM's it goes down to about 2k. Any idea why?

 

that kinda happens to me, too. ill be on the highway going 60 or 70, have to slow down, then merge over a lane, and speed back up, and it just really slowly begins to rev, maybe by about 100 rpm. then it finally downshifts(automatic), and she screams from about 2400-3800RPM(i believe shift is at 3800, dont have a tach). i'm wondering how i can improve the response on my tranny, maybe a shift kit??? anyway, yeah.....

 

bump

 

It shifts like that becuase all of the six's power is made down low. Makes 160hp at 3400rpm. Anything above that and it packs up and goes home. The six is not a fast engine, its a working torque engine. What are your MPG figures? Check fuel pressure. When is the last time you had a tune up?


Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Sunroof, CD player with 2 10" subs and some 32" BFG Muds .

Check out my Gallery for a look-see.


Then theres:
99' Mustang GT 4.6L
88' F-250 Superduty 4x4 351/c6
95' Mercury Cougar 4.6L V-8
80' E-350 300/6 with a
3 spd column shifter. Top speed is 65mph, Go Baby Go!

 

Just clocked in my city MPG today, got 14.5. Highway, i've clocked once and got 18-19.

Tune up, not sure didn't check when I bought it a month or so ago. When I bought it changed fuel filter, tranny filter, air filter just changed the oil in it today. The wires/plugs/cap look in good condition.

I can't even hit 3400 rpm, I can mash the pedal down to the floor(and I mean to the floor) trying to pick up speed, and it'll hit 3200 rpm or so and then go right back down to 1500 or whatever it was at before I smashed the pedal down, there is no redline on my tach either.

 

There is no redline because the same tach is used for all engines, and they all have different redlines. I don't know about six's and autos but that doesn't seem wrong. You'll just have to find someone with an auto and six. I think thats good, because it doesn't make squat for power anyway. If you want to check my theory, lock it in 2nd gear and you'll see what i'm talking about.


Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Sunroof, CD player with 2 10" subs and some 32" BFG Muds .

Check out my Gallery for a look-see.


Then theres:
99' Mustang GT 4.6L
88' F-250 Superduty 4x4 351/c6
95' Mercury Cougar 4.6L V-8
80' E-350 300/6 with a
3 spd column shifter. Top speed is 65mph, Go Baby Go!

 

The gas mileage looks right, so you seem to not have any power issues. Power issues imediately reflect on gas consumption.

Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Sunroof, CD player with 2 10" subs and some 32" BFG Muds .

Check out my Gallery for a look-see.


Then theres:
99' Mustang GT 4.6L
88' F-250 Superduty 4x4 351/c6
95' Mercury Cougar 4.6L V-8
80' E-350 300/6 with a
3 spd column shifter. Top speed is 65mph, Go Baby Go!

 

I've accidentally locked the thing in 2nd many times(Not paying attention and putting it into drive, and not seating it all the way and it slip into 2nd).

Wouldn't it mess up the tranny if I put it in 2nd and went to high of a MPH?

I think one thing might have to do with my gears(3.08's).

I'm not too worried about it, it's reliable and it goes fast enough for me.

 

No it doesn't hurt the transmission. 3.08s are the big thing to make your truck slow.

Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Sunroof, CD player with 2 10" subs and some 32" BFG Muds .

Check out my Gallery for a look-see.


Then theres:
99' Mustang GT 4.6L
88' F-250 Superduty 4x4 351/c6
95' Mercury Cougar 4.6L V-8
80' E-350 300/6 with a
3 spd column shifter. Top speed is 65mph, Go Baby Go!

 

My '95 300 I6 has 90,000 miles. It gets about 17.5 mpg mixed highway/street. Acceleration if good, a little sluggish below 2000, but from 2000 on up to the high 3000s it really moves nicely (for a stock 300). I have no problem getting to 4000, but normally don't exceed about 3600. If the mid to upper rpm sluggishness described above makes me think about an exhaust restriction, perhaps a partially plugged cat. (I assume you have a fresh air filter and the truck is tuned up correctly--BYW, I picked up 1 mpg just by doing cap, rotor, wires, and plugs)

INLINE SIX POWER!
300 Cubic Inches of Low RPM Truck Torque! And twin-I-beams too!
"Drive a stick young man! There'll be time for automatics when you're old and unable."

 

I have an 88 I-6 and don't have any problem hitting 4000 RPM (I never do it though, well maybe 1x last night.) An earlier post on this site described a similar problem and it ended up being that the carpet or floor pad in the truck stopped the gas pedal from going all the way down.

 

[updated:LAST EDITED ON 02-Jul-02 AT 08:50 AM (EST)]I barely do an highway driving, and it's about 10 minutes roundtrip a week.

As I said earlier airfilter is a month old, and about the tune up i'm not sure, when I bought the truck a month ago I didn't ask when was the last tune up. The wires/cap/plugs look in good condition.

Would me having an auto make a diff in being able to achieve the RPM's?

How would I check out if the cat is clogged?

 

Not sure if this is the best procedure but it is from http://www.salemboysauto.com/faqs/faq-51.htm

"If the problem is simply the engine loses power, a plugged catalytic converter can also cause that problem. A shop can test the cat by drilling a small 1/4 hole in the pipe just in front of and behind the cat. With the engine in park, raise the rpms to 2,000 and feel the air or exhaust coming out of both holes. Is exhaust coming out of the front hole at a higher speed and at a larger volume than the rear hole? If there is an obvious difference of pressure between the two drilled holes, the cat is plugged and needs to be replaced. If you decide to do your own test, you can close up the two drilled holes afterwards either by having someone weld them up ($10-20) or simply screwing a big sheet metal screw into the hole."

Before you drill holes, I read somewhere where you can test for general exhaust restrictions just by (I think) a vacuum gauge, without drilling holes. Not sure, but maybe someone can explain it.

 

I don't have a problem with power, but I've got a 5 speed. Ford's AOD's suck a lot of power.

I agree with the idea of the catalytic converter. You can test a heavily restricted converter with a vacuum gauge. You just hook it to a manifold vacuum fitting and rev the engine. The vacuum should stay the same or even increase with rpm at part throttle. If it drops the converter is plugged. It should also recover immediately when you return to idle. You can also test it with a pressure tap in the O2 fitting. If you get more than 2-3 psi backpressure in your exhaust you have a restriction somewhere in the exhaust.

You should also check to make sure you are getting full throttle opening. The cables stretch over time and you could have something under the gas pedal. Also check the ignition timing and make sure the brakes aren't dragging.

I think you mentioned checking the fuel pressure. Did you check it with and without the vacuum line attached? It should be around 40-45 with the line on and 55-60 with it off. With the gauge still on, rev the engine. The pressure should stay the same, if it drops you have a fuel system problem. If possible, drive the truck with a vaccum gauge on it. With the throttle floored the vacuum should ber zero throughout the rpm range. If you start pulling vacuum at high rpm the FPR will start to pull fuel pressure in response to the vacuum. One easy way to check this is to pull the vaccum line off the regulator and plug it, then go drive the truck. It will run very rich at low rpm, so don't drive it this way for long; just long enough to see if it helps.