camaroeater

Its like hitting a rev limiter when i get around 3500 rpms. The rpms will go up to about 5K, but the power just isn't there.

I recently did a distributor cap, rotor and plugs gapped at .054 (regapped to .052, same problem) fuel pressure is at 35 psi and 44 with vacuum line unplugged. Timing is a 12* degrees with 87 octane fuel. No codes found running a Koer/Koeo test.

Ive noticed that the power is there throughout 1st gear, but not with 2nd, 3rd and 4th the gear. There is no backfiring, smoking or anything.

The only thing i can think of is clogged cats possibly. The bbl X pipe I have is about 6 years old, but I ran it without a smog pump for two years, so maybe they are melted??

Thanks guys...I would appreciate any input!

dawson1112

Im trying to understand, you say its like hitting a rev limit, but that would mean it wont rev past 3500, if its going on past to 5k then its not limited revs.

Running with out a smog pump will not melt your cats, there are thousands of guys running cats with no smog pump and no problems at all.

The problem you are describing sounds like a slipping clutch (manual trans ) or a slipping transmission ( automatic ).

Obviously if the revs are there, and its not pulling then you are slipping in the drive train some how. With a manual trans first gear takes less engine power to to get the same torque to the wheels than any of the other gears. To test this theory, pull hard through first gear , then skip second and go right to third. The engine should bog down a little, if it revs hard with out feeling any pull, then its your clutch slipping.

bluebeastsrt

That sounds reasonable. If the motor is running fine with no codes I'd have to agree with Dawson. Is it a stick or automatic?

camaroeater

Sorry, let me explain better. It goes through each gear as it should, but around 3500-4000 the power is just not there. I can still go in each gear to 5000 rpms. Its the same thing when you stay in a gear to long and the valves just float. So basically what should happen around 5300 tmps happens around 3500. Also, the clutch was replaced 6 months ago and is 100%. Although i do have a bad 2nd to 3rd sychro and know the transmission is about done. So maybe transmission slipping??? I heard on here that t5 don't slip, they just stop shifting.

Thanks for the help guys

stangrookie302

Just throwing it out there, it does sound like a drive line issue but how about a flat cam? How old is the engine? Maybe your exhaust valve ain't opening up all the way to get all the carbon out of the cylinder to where you don't have an adequate power stroke. Maybe some oil is slipping through the rings just enough to not have smoke but enough to disagree with the air/fuel mixture. Does it sound like a sewing machine when you get to 3500 RPM's?

dawson1112

Valve float is when the valves bounce back off the seat at high rpm due to springs not having enough seat pressure. Engine falls on its face, rpms will go no further. The engine will also backfire and pop like crazy or develop a severe miss. This will result in some serious damage if not rectified, such as bent push rods , valve stems, and in severe cases damage to the pistons.

IF your engine is reving smoothly to 5k, but the car stops accelerating something in the drive line is slipping. Any thing to do with the engine ie,, fuel pressure , spark , or semi clogged cats would be noticeable in the way the engine sounds.

A new clutch can slip just as easily as an old clutch, depending on what brand you used. If you got a cheap ebay clutch then expect it to slip.
T5 transmissions don't slip, they grind or just stop engaging all together.


Perhaps your 87 octane is not agreeing with your 12* btc timing and you are experiencing some slight ping. I suggest you temporarily set timing with a light back to stock 10* btc and see if it helps.

I would also suggest you post a video of this happening so we can see for our selves what is going on. Maybe your having a hard time describing your issue or I am having trouble understanding it, a video would clear things up tremendously.

Chromeshadow

Could also be the centrifugal timing advance is not working properly.

mbeer

Try a tank of premium gas in it before you reset the timing.

dawson1112

Setting the timing takes 5 min. He would have to wait till he was on empty then fill it with premium, plus that costs more. Backing the timing off is free.

camaroeater

The engine has about 240K on it, so i know its time for a rebuild. Ive set the timing so many times on this, I'm sure its set right. I can rev each gear over 5k, like it always has, but around 4k you can feel it struggle so very slightly you might not even notice it. Im thinking its mostly likely clogged cats from running no smog pump for 2 years in temps of 115*. Other than that id say weak fuel pump,something in the engine or maybe the spark plug wires (wires are about 4-5 years old). The clutch was replaced with a Ram HDX along with all Ford OE parts for every other part in the clutch system.

Thanks everyone for the input!!