Just bought a '88 regular cab runs great but there is a f@#%ing annoying rattle coming from under the efi set up. At first I thought it was a heat shield but quickly learned it wasn't. It happens at higher revs like right before shifting into second or third. Been looking for loose stuff banging around but couldn't find anything. Anybody had this problem? If it's just something loose I guess I will eventually find it, just worried it mind be something more serious.

Any help very much appreciated!

 

is it a rod knock?

 

You say it happens at higher rpm..... how's the timing? It might be pinging.

 

I don't think so only because it just doesn't sound right to be a rod nock.

It also does it when I am in third getting close to shifting into fourth and traffic slows down and I need to slow down a little so I take my foot off the gas and leave it in gear. Could that still be a timing issue?

 

Have you ever shaken a good PCV valve and heard the check ball valve rattle? Does it sound like that?

 

I just replaced my PCV so I took it out and shook it. It sounds similar but the sound while driving sounds more like metal against metal than metal against plastic.

 

i have something similar to what you have described, mine normal rattles once i hit high rpm's and then left off the gas without a load, like as if i clutch it, it does it other times but this is when it makes the most pronounced rattle. it appears to be my cat heat shield as well as maybe a place where my exhaust is coming apart.

 

Same here
It only happens on a hot engine when it is under load. Usually when shifting to a higher gear and flooring or on steep hills and flooring. But i've learned to live with it by backing of the gas or speeding up gradually.

 

i gots a thread about mine too, kinda sounds like a bad T-chain but not quit loud enough, look at my thread i have a vid of my engine and theres 2 others, mines the quietest of the 2, im guessing the timing guides are gone off the other vids, i was just in there on mine and there still good, i might have a bad/old chain tho..

 

Thanks I'll check that out.