Can the timing chains in our cars become loose and cause the valve timing to be a little slow of where it is supposed to be and cause an idle problem. I need a little education on that since I hear both sides of it. I have to replace the timing cover gasket anyways so while I am in there I might as well replace that if I have to. The car is my 89 RS with a 2.8. The car has just under 130,000 miles in it.

I am still having an idle problem like it is a vaccum but I fixed all the leaks that existed. Could there be anything that causes the idle to be erratic that is not a vaccum leak? Worn injectors, FPR, other stuff. I also got a bad header leak right at the head (broken bolt) I know that that can cause problems.

 

The loose chain can cause low vacuum readings due to incorrect valve timing..The valves are opening to late compared to the position of the piston.A worn camshaft can have the same affect,the valves wont open as much creating low vacuum readings.The stock chains arent high quality,I replaced mine at 129,000 and after removing the dampner you can see how much slop was actually in the chain.Once I replaced it ...it was a major improvement in the way it ran.I also have a few broken manifold bolts ,but instead of removing them I plan doing a head/camshaft swap.It doesnt seem to affect the performance/idle at all?I think you need to do some testing to narrow your problem down.Fuel system/computer codes/ignition system etc.

 

No codes, plugs and wires are new, I am getting a new cap soon. Sometimes my car will idle smooth but only for a couple of seconds. Then it may die or idle high again. In this case I will replace my chain but leave the cam alone. I am planning on a mild motor build here soon.

 

If you are taking the cover off anyways, I highly suggest a new chain while you are already that far into the motor. To change the cam, the entire intake mani has to be removed.

 

That was my same thought. I'll put a new one in here pretty soon. Should I get new gears too? I won't mess with my cam in this motor.

 

ANY TIME you have to dig into a third gen, do what ever work you planed or that needs to be done, while you are in that far...

If you need to replace the timing chain gasket and the chain has 100,00+ miles on it, REPLACE THE CHAIN TOO! Do you really want to replace the gasket only having to do it AGAIN when you go back in to replace the timing chain?

For example, the mechanic that replaced my fuel pump used a tranny jack to put the tank back and put a small hole in the tank. He now has to remove and repair the tank. While he has the tank down for repair, I am supplying him with lowering springs when he re-installs the tank. I get my car lowered for only the cost of the springs and the labor for the front!!

 

I do that everytime I work on my car now.