janag

I have a 1998 F150 4 x 4. After the truck gets warmed up from driving about 10 to 15 minutes, there is a knocking noise under the truck on the driver's side. At first I thought it was a rod knocking, but it's under the truck, not in the engine. I had the catalitic converter checked and it's okay so I have no idea what the noise is. It's almost like something is loose and hitting on another part of the undercarriage, but it only does it after the truck is warmed up and it does it sporadically. Can you help? It's driving me crazy trying to figure out what it is.

Thanks!

dewman

Welcome to the board!

Not sure what to suggest, but let me ask a couple questions. Is the noise happening when the truck is driving, or sitting still? If the noise occurs while driving, does it happen when you are turning, or driving straight? We have some good mechanics here and your answers should help them to narrow down the problem.

josh_truck

is it a V8? if so check your manifolds... mine was ticking and i found out one of my bolts holding on the manifold snapped off.

icantdrive55

Not sure if your motor has the VVT mechanism for cam timing, but my brand new '09 was bad from the factory and had to be replaced. The knock only manifested itself at an idle after engine had reached operating temp. It was a deep knock--like a rod knock--and I couldn't pinpoint the source of the noise.

If your dealer says your motor had VVT in '98, have them check out the cam phaser.

janag

It happens when I'm driving. It's a V8. I got under the truck and it seems like it's coming from the exhaust, but the man at the muffler shop said that everything was fine underneath. Of course it wasn't making the noise by the time he looked at it becasue the truck had cooled down. I don't know about a VVT, but I will check with the dealer. Maybe it's my exhaust and the feller didn't know what he was talking about. At least it's not in the motor.

The other problem I'm having is my truck idles rough and does like a hesitation while driving and it doesn't have as much power as it did. I have changed several things on it like the EEG (?) valve, fuel filter and other things that have to do with air intake, etc., used almost every kind of injector and carburator cleaner and some stuff called Restore and nothing helps. I'm going to do a tune up, but I don't think that's the issue. Someone said it was carbon buildup and the intake and outtake needed to be taken off and the carbon cleaned out.

I know ... we haven't finished figuring out one thing and I bring up another, but I'm a single parent and don't have the money to get some high class person to take the truck and "fix" it for $2,000.00 or whatever. I appreciate you help!