Truck acting crazy

[paixbouche]

Hi Guys,
Truck idles rough, very hard start, will drive fine one minute, then service light comes on and truck won't climb the simplest incline. Sometimes, it will start one kick. Sometimes it won't start at all. When it starts fine, everything works fine. However, when I am driving, and I try speeding up, it acts like its going to cut off and I hear something like a knock in the engine.Light goes off and everything seems fine. On the occasions that I have brought it to the shop, there were no codes.
I have changed spark plugs, wires, rotor, cap and I had the trans. overhauled. What are the symtoms of an air sensor or oxygen sensor. Any help is appreciated.
Thanks Guys.

[old school bigdadd]

Originally Posted by paixbouche

Hi Guys,
Truck idles rough, very hard start, will drive fine one minute, then service light comes on and truck won't climb the simplest incline. Sometimes, it will start one kick. Sometimes it won't start at all. When it starts fine, everything works fine. However, when I am driving, and I try speeding up, it acts like its going to cut off and I hear something like a knock in the engine.Light goes off and everything seems fine. On the occasions that I have brought it to the shop, there were no codes.
I have changed spark plugs, wires, rotor, cap and I had the trans. overhauled. What are the symtoms of an air sensor or oxygen sensor. Any help is appreciated.
Thanks Guys.

It sounds like you might have a fuel delivery problem. If you have more than 60,000 miles on your fuel pump, it could be suspect. I would recommend having your fuel pressure checked. If it is the fuel pump, be sure to replace the fuel filter and sock, and then replace the fuel filter every 10,000 miles. I don't remember if your engine is a TBI or Vortec, but if it is a TBI, Autozone sells AC delco fuel pumps fairly cheep (under $50.00) and with a lifetime warranty. If it is a Vortec engine you have to buy the fuel pump module, which is very expensive ($250.00 - $600.00). If you are going to keep the vehicle for a while I would recommend that you buy the fuel pump module from Autozone. The reason is, they offer a lifetime warranty, the dealer and other autoparts stores don't. So in the longrun you are better off getting it form Autozone, because this pump is GOING to fail again, so why pay for it more than once. I hope this helps you. Good Luck.

[toivo]

check if egr is closing all the way at idle and check for vacuum leaks at the base of the tbi if thats what you have.

[dirty dan]

It would help alot if we knew what year and engine you have!