Hey,
I just bought a 1990 f150 XLT lariat with 59,000 original miles from a 88 year guy who took great care of it. Today i noticed a slight rattle (like a paper clip in a glass) only when I accelerate. Any ideas? It it not very loud but still concerning and Very annoying.

 

Perhaps the timing? a loose cable? Or worse? It does not appear when revving in park. I did put in my first gas today. The first few days there was absolutely no rattle.

 

Look at the base ignition timing with the Spout plug removed.
It should be set to 10° Btc.
The motor should be ok on 87 octane gas howerver if there are chamber deposits the octane requirement could go to 89.
Normally the Knock sensor would pull the timing back if to much timing is present.
It may be the gas you put in.

 

thank you! Yeah I will bring her in to get looked over by a Ford mechanic. So probably nothing too serious then right?

 

So if a valve rattles a little, does that necessarily mean anything long term? I know the guy only put 1200 miles in it all of last year. The spark plugs have some rust on them as well. I will most likely change them and the wires. Otherwise teh truck is immaculate. Is the 5.8 L V8 a goog engine?

 

the 5.8 is a good engine (351 cu/ in.).

 

last question...so if the rattle is from bad timing, or gas, or carbon build up etc.....does that mean anything toward the life of the engine? IE Does it mean the engine is damaged and will cause a problem long term? Thank you so much for all the advice. I am new to trucks and so far love it!

 

I had a 95 with the 5.8, and it developed a "chatter" at around 140k miles, which occurred on acceleration, especially uphill/under heavy load. It never chattered when using 93 octane - only when using cheap gas. I was told it would require a rebuild in order to fix it. That got old fairly quick though. I prolly would have done a rebuild if I had kept that truck. Hopefully yours isn't the same situation.

 

I don't know a lot about the mechanics of my truck, but if by "chatter" you might also mean "pinging", this could be worth a try. Advice is that when the Mass Airflow (MAF) sensor gets build up, all sorts of problems are fixed using:



I'll be doing mine today after I get the truck back from the shop. Having a fuel injector flush and new shocks installed this morning. Some say take it right out using specific tools, whilst others recommend leaving the MAF intact and giving it a good spray right in the housing. I'll be doing the latter.

My two cents,

Jay

 

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