dcc1993

Hi guys newer member here just wanting some opinions. I have a 1993 f150 4x4 xlt 5.0 completely factory. I had the truck since 12k miles, since I got it there always seemed to be something holding the power back. There always seemed to be too much back pressure, I am assuming the cats were clogged, not sure if this has anything to do with it but three times i had too replace exhaust cause of rotting out behind the cats. Now there is another exhaust leak which I have to check out but am thinking I am going to replace from the manifold back. I think there is 4 cats on this truck. Is there an upgrade for this system, I also have the factory smog setup still operating, air pump seems to make hissing noise during acceleration. Have to mash the peddle to the floor to climb a hill and I am sure this engine has plenty of power and there is something else holding it back. Truck has been sitting for 4-5 years and I am getting it road worthy as we speak. These issues were before it sat.There is 72k miles on it now. Thanks for reading , I am looking forward to any opinions on these issues or any other advice on something I can upgrade on this truck to improve performance. Truck has always been a dog on gas but if it was performing well I would just figure it went with the territory.

Shagg

One of the trucks I have is a 1990 f150 that sat for a while, and replacing the fuel filter caused a BIG difference in the truck's performance. I honestly wouldn't be surprised if all those exhaust leaks were effecting the truck's power. And four catalytic converters does sound like a bit much, I doubt it could hurt to cut that number in half.

Steve83

No, that's just how they run.You can't detect exhaust backpressure from the driver's seat. It takes specialized equipment & the training to use it properly.That's called "guessing", and it's no way to diagnose or repair a vehicle. It certainly doesn't justify blindly swapping parts.That's usually caused by commuting, instead of making long drives that fully heat-up the exhaust, to cook all the water out of it. But depending on your location (put it in your profile), it might be due to road salt. And you might be getting cheap replacement parts, instead of OE-quality or better.Why stop there? Why not replace the whole truck? You'd be guaranteed to get better performance, acceleration, MPG, & a warranty. Randomly picking one part or any group on such an old truck isn't likely to fix or improve anything.No. And that should be an indicator to you how little you understand about it.Not really - it's already the highest grade available, unless you rebuild it in stainless steel.Good. Keep it that way, and the truck will run better longer for less money.No, the air pump makes a puffing sound all the time. The hiss is the exhaust leak. Click this & read the caption:


(phone app link)Probably lack of maintenance.


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(phone app link)That certainly didn't help it any. You NEED to change the brake fluid & coolant ASAP. And the tires are probably unsafe - check their dates.


(phone app link)That supports the commuting theory. Mine is approaching a million miles on the engine (no rebuild or repairs) & exhaust.If it performed better, you'd just press the pedal more, and burn even more gas. With it running perfectly, you should expect 12-16 MPG, depending on how you drive. If you drive like there's a wine glass on the dash, and try not to spill it, you might get 17 (assuming the speedo is calibrated).


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raski

You can check for exhaust restriction with a vacuum gauge, although I do not believe that is your problem. The CATS aren't going to melt down unless the engine had a long term drivability problem. You do need to provide more information such as transmission type, rear end gearing and RPM speed when it appears to be "bogging " down. Could the transmission/clutch be slipping? Is the engine underperforming, we would only be guessing without further investigation. I would start with a good tune up, timing check and fuel filter change to start.

dcc1993

Steve thanks for replying , I do understand my truck, haven't been under it in years so sorry it has two cats, last vehicle i replaced a cat on had two precats and two cats so was not sure off hand how many there were. I see today I can replace it with one cat, and that is what I was asking for. Every problem I wrote about is before this truck sat. I didn't just sit in the driver seat and say I think there's too much back pressure? My exhaust leak now is one of my cats, it looks swelled and split right down the middle, and it actually runs a little better now, and the exhaust coming out the tailpipe before it split (the pressure) seemed real low. But either way I need to replace the cats back now, I am not guessing and throwing parts at it. It corroded two sets of factory exhaust and the others were aftermarket and maybe were poor quality but no different then any other of mine or my wifes vehicles that never had any exhaust issues. Been getting 8 miles to a gallon since I got the truck with 12k miles on it. I maintain the truck regularly too. No need to write " I don't understand my truck", I do, its just been awhile and the number of cats had nothing to do with what I was asking or I would have checked it first. But after talking to someone today who had same issues after replacing his cats made it run better, and he never had to replace any other pipes from rotting also. Just looking for help and suggestions,I appreciate helping replies , if you feel the need for sarcasm please don't respond. I hope to get some more replies from you for stupid questions I may ask in the future , but please understand I do know what I am doing when it comes to working on automobiles, Its just been awhile and I don't put to paper what is in my head well.

dcc1993

Thanks raski, I just replaced cap,rotor,wires,plugs,fuel filter, all heater and radiator hoses. Did a coolant flush, replaced complete braking system front and back and the rusted lines(not the rabs unit), also replaced the master as it was dripping down the booster and flushed all the brake fluid. Going to get the new exhaust on and see if there is still any power issues. I am replacing the cat back due to rotting and leaking . If there's still issues I will get the info you asked and post it on another reply, thanks for replying !

dcc1993

Sorry forgot to say the tranny is not slipping.

Steve83

I can only reply to what I read. The more (relevant) info you supply, the more-appropriate our replies & suggestions will be to your situation. Read these captions:


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