A confusing Problem...
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Freshman User
Joined: Aug 2007
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A confusing Problem...
My '90 F150 4.9 has some issues...
When I first start it up it stumbles and dies but ALWAYS on the second try it starts right up...the engine revs itself up a bit and then after about 10 second it goes to Idle at about 700-900(somewhere between there it depends on the day)The engine misses not constant though. It will do it for a little bit but then it will quit for alittle bit.The engine does not like to rev over 2000 rpms, it will get there but it will miss like a mother and it has NO power.When going up a small incline it has to be in 3rd gear with the peddle 1/2 downWhen I first got the truck It would rev to 2500 rmps no problem, It WAS powerful until I changed the spark plugs and wires. After that the CAT got clogged and I loosend the pipes of the manifold a little to let the engine breath.
people told me the Head could be bad, a pistons shot, head gasket, the CAT is causing the miss, the weather is causing the problem. I don't know what to think.
You guys know more about the 300 than the people ^^ above
When I first start it up it stumbles and dies but ALWAYS on the second try it starts right up...the engine revs itself up a bit and then after about 10 second it goes to Idle at about 700-900(somewhere between there it depends on the day)The engine misses not constant though. It will do it for a little bit but then it will quit for alittle bit.The engine does not like to rev over 2000 rpms, it will get there but it will miss like a mother and it has NO power.When going up a small incline it has to be in 3rd gear with the peddle 1/2 downWhen I first got the truck It would rev to 2500 rmps no problem, It WAS powerful until I changed the spark plugs and wires. After that the CAT got clogged and I loosend the pipes of the manifold a little to let the engine breath.
people told me the Head could be bad, a pistons shot, head gasket, the CAT is causing the miss, the weather is causing the problem. I don't know what to think.
You guys know more about the 300 than the people ^^ above
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You changed plugs and wires and the cat got plugged? How?
Is it wired correctly? Some of what you describe sounds like you have a couple of plug wires reversed.
You loosened the pipes...what pipes? From the manifold to the head? From the manifold to the cat?
Are you subject to smog inspection and test that requires the cat? If so, get it replaced. If not, remove it. Having the exhaust puke out in the engine compartment is an invitation to fire and that really drowsey feeling followed by disaster.
And yes, it could be any or all or none of the ideas suggested. Go back to the basics. The last thing you did to it was_____ and it started to run like crap then or when?
Is it wired correctly? Some of what you describe sounds like you have a couple of plug wires reversed.
You loosened the pipes...what pipes? From the manifold to the head? From the manifold to the cat?
Are you subject to smog inspection and test that requires the cat? If so, get it replaced. If not, remove it. Having the exhaust puke out in the engine compartment is an invitation to fire and that really drowsey feeling followed by disaster.
And yes, it could be any or all or none of the ideas suggested. Go back to the basics. The last thing you did to it was_____ and it started to run like crap then or when?
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Freshman User
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I loosend the pipes that go down to the Cat off of the exhaust manafold. Yeah I don't understand it either, I changed the plugs because of a small miss, but then I drove it around the house and it was missing worse. I didn't understand that much so I took it to a friend and he said the wires were shot so I bought new ones and he put them on. He took the Dis Cap off to make sure everything was fine underthere. I tried to drive it and it had no power. I went back and we checked the exhaust temps and they were at 495 and 387 right before the 1st Cat.
We don't do any E-check here, which is nice Because I was thinking about taking both CATs off get a 2 into 1 y pipe to connect to the pipes that connects to the mannifold. Then after that I have a 30" Cherrybomb I was thinking about. But I don't know how to hook it all up, I don't have a welder to weld it on. Can I Clamp it all on or is that a bad Idea?
But Before I do the exhaust work I need to figure out why the engine is doing its thing so I don't spend all my money on exhaust work to figure out that the Engine has a dead cylinder or something.
We don't do any E-check here, which is nice Because I was thinking about taking both CATs off get a 2 into 1 y pipe to connect to the pipes that connects to the mannifold. Then after that I have a 30" Cherrybomb I was thinking about. But I don't know how to hook it all up, I don't have a welder to weld it on. Can I Clamp it all on or is that a bad Idea?
But Before I do the exhaust work I need to figure out why the engine is doing its thing so I don't spend all my money on exhaust work to figure out that the Engine has a dead cylinder or something.
Cargo Master
Joined: Sep 2007
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From: Wahpeton ND
Buy a Hayneanual! that will show you how to do OBD1 diagnostics using nothing but a test light. dont remove your cat if you have two o2 sensors. itll run worse!
Also you may have bad timing try adjusting your timing once its running. the jam nut onthe dist may just be loose.
ford also had a "jumper" chip on the so called thin film dist check into that its replaceable with a wire.
Buy a HAYNES MANUAL!
Also you may have bad timing try adjusting your timing once its running. the jam nut onthe dist may just be loose.
ford also had a "jumper" chip on the so called thin film dist check into that its replaceable with a wire.
Buy a HAYNES MANUAL!
