I have a problem with my 97 4.6L. When I start the engine cold, it makes a rattling noise as it turns over and is really rough until it gets up to idle. It has been getting progressively worse as time goes by, and I don't want to get stuck sometime.
Once the engine is running it runs fine and doesn't throw any ECU codes.
For this sort of problem I don't even know where to start.

 

what do u mean by rattling on start up?? the rough idle i would suspect is the idle air control valve in top of the throttle body is probably dirty. how many miles does she have on her??

 

She's just shy of 110,000. As soon as it cools off I'll go out there and record it starting, then post it. It doesn't have a rough idle once it's started, and once it's warm it starts just fine.

 

I think its your IAC sticking as well.

 

I just cleaned the IAC Valve. There was a little carbon buildup but it wasn't bad. That wasn't what was causing it. If I had to guess I'd say my starter motor is going bad, but I'm not sure. The engine turns over just fine, but for a second or two after I stop cranking I hear the rattling. Once again, it only does it when the engine is cold.

 

just a shot in the dark but on my 85 it was cause by my temp sending unit may check it

 

If the sound is coming from the internals of the engine, it may be piston slap.

Steve

 

I believe it may be the starter. I suspect this because it first started happening after I went through a sizable mud puddle. The bottom got a good covering in mud, so much so that my transfer case motor went out and I had to replace it. As I understand it, the starter is right on the bottom of the undercarriage. Could this explain the noises I've been hearing? Is it worth looking into, or would I just be wasting my time?

 

If it isn't affecting the normal operation of the vehicle, and you have oil pressure, I wouldn't let it bother me. Do all you can, and if you can't figure it out, just accept it and go on. If it's a starter problem, it will become evident the day it won't crank! But seriously, don't lose sleep over knocks and ticks. If you have done all you can to find it, and you are running the correct fluids, there's not much else you can do. If it's a serious problem, it will make itself known when it's ready. But all truck have their weird ticks and bumps. Mine makes a "lifter tick" noise on startup when the initial engine temperature is between 120 and 160 degrees. It doesn't do it when it's cold, or when hot. Go figure that!

 

I know that I'm going to do everything I can to make it work. And I'm not losing any sleep over it......yet. I just like to keep my truck in perfect working condition as much as I can. The longest time my truck has been out of
commission was a week when AutoZone ordered the wrong part twice. Generally if something goes wrong it takes me less than 3 days to fix it.

I also really don't want to get stuck. If something goes out at the inopportune time I could have problems.

What I'm really looking for is whether it would be worth my time to check the starter.

 

You can check it, but it's cranking the truck fine. What are you gonna do? Replace a working starter? My point is, you might get another 200,000 miles out of it!

 

just check the starter bolts make sure they are still tight. also make sure the connections are good the cables corrode and rot over time. im with chester why replace a starter that works they can be around 100$.

 

if its what happen to mine, the shaft and e-clip for the gear when engaged by the bendix was damaged. shaft was chipped and the e-clip what sheared...


wait and see its not a big deal. mine still started even with those problems.

 

Hmmm, not much description but my 97 ford has a noise as well when it starts...maybe the same? It sounds as if the fan blade is barely touching the fins on the rad...giving you that tingy noise. Is that closer to your "rattle" noise? I haven't found the problem but nothin's broke so what can you do. Good luck.

 

Thats almost exactly what is sounds like. Checking the fan might be a good idea. I still need to get someone to start my truck with me hovering over the hood so I can figure out exactly where the noise is coming from