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what could be wrong with my truck i got a 93 f150 4.9l just rolled over to 130k. i drive a Toyota to work and back and drive the truck every other weekend and recently i tried doing a 4in lift in the front with coil spring spacers and f250 leafs in the back with 2in lift blocks and when i test drove it it seemed like it didn't have any power, i couldn't get the alignment done so i took all that stuff off and now my truck has no low end power. i don't know if that's stuff had anything to do with it but when i go around corners i cant even sequel my 31's in 1st. i had flex pipe coming out duals out passenger side for exhaust and recently it just broke so i just stuck a straight pipe with a turn down for like a muffler end, exiting before the rear axle and i don't think the exhaust system has anything to do with this either. what could be wrong? scanned for codes none came up and everything under the hood seems OK.
The 4.9 likes a little exhaust backpressure to build low end torque. You should get the exhaust put back to the factory configuration. Also, look around for vacuum leaks. Its possible you pulled a vacuum hose loose or something.
wouldnt the cats give it enough back pressure? and i have replaced vacum hoses so they shoulnd be leaking but one could have just poped off i will take a look
wouldnt the cats give it enough back pressure? and i have replaced vacum hoses so they shoulnd be leaking but one could have just poped off i will take a look
Im not sure if they would but I have read in a few places that the 4.9 is very sensitive to changes in the exhaust.
Also, Im basing my suggestion on what you posted had been recently changed, and what could have been done during the installation and removal of the lift. There are several possibilities really, just trying to break it down by probability.
Have you check the fuel pressure at the rail? Are all of the spark plug wires intact? Any noticeable missing, or hesitation in throttle response? Might do a compression test on the cylinders. I believe you can borrow a gauge from autozone with a deposit, or just buy one. They aren't expensive at all and a good diagnostic tool to have around.
yeah i just cut a slit in the pipe and welded a peice of flat stock in and it works for now. i would change it back to stock but i got headers i want to install this summer and i dont want to wast the money cause i am short on it right now. yeah cause yesterday it rained a little bit and i couldnt even spin the tires going around the corners in first gear.
what about a vacuum leak? I know I've bumped vacuum lines while working on various thing on the truck before, then it didn't run so hot. Started going over things trying to find see what I could have screwed up, then find a broken or disconnected vacuum line.
FWIW, my '88 was still full of torque, even when the exhaust system ended at the second cat, and quiet, too. Plowed snow with it like that. That being said, the wide open flow of the exhaust in my 302(different engine, but some basic principles apply) makes it a dog at the low end(but it SOUNDS like a monster, and that's all that matters, right?).