92 Loyale,

 

this has been discussed somewhere but my search has been unsuccessful.

 

I also know it is pretty hard if not impossible to diagnose this, but FWIW, I have a slight miss on this engine. It runs well on highway but when idling, I can tell. The spark plugs and plug wires are from this summer, although the latter were the cheapest kind (you know $9.99 deal) so I wonder if they cracked inside or something.

 

What else can cause a miss?

dunno.. my new wagon does the same thing, miss at idle but once you give it a couple hundred rpm's it smooths out.. i figured the spark plugs are old.. going to change them next..

 

not sure what else would cause it..

I am going to change the plug wires to something better instead of the cheapest set from Advanced Auto Parts (that's all they had at the time).

Valve leakage can do that. Do a vacuum test. A leakdown test can pinpoint it, also.

 

A rich/lean mixture at idle is another possible culprit, as are vacuum leaks.

I didn't know that.... Interesting.

I pulled a compression check when cold and got 150 on one side and 90 psi on the other side. But when it it hot, I wonder if the head expands and seals the crack.

 

It had an overheating incident a while ago.

 

I doubt there is any point in compression/leak down tests because I don't plan to do anything with the engine.

ohh something else... mine runs extremely rich when its cold.. you can smell the gas from the exhaust.. prolly something to do with it.. lol and my check engine light is on.. maybe a bad 02 sensor..

 

gotta see what the code is for that engine light before i can do much about the idle miss..

I too have a permanent engine light on, something is setting the code. I don't know how to pull the codes on it.

V.V.:

 

Wait a sec...150 psi vs 90 psi IS a problem, if the reading is accurate. The test should ideally be done at operating temp, so you did nothing wrong there. I'd investigate that situation a bit further. At the very least, redo the compression test.

 

I like the suggestion of using a vaccuum guage for troubleshooting. That's becoming a lost art.

 

As far as the miss, I don't think it would be a result of low compression. In other words - you have multiple problems. I would definitely start with the ECU codes before throwing parts at it.

 

I absolutely HATE those cheap-rump roast Autozone plug wires. Do yourself a favor and buy some OEM's or equivalant quality wires next time around.

 

good luck, John

Agree about the cheapest plug wires.

 

Maybe there is something wrong with my compression tool, becase the next time I tried to pull compression, it registered 0 on all cylinders. I bent it slightly at the tip, and ever since then, it doesn't work.

I like mine with a standard milton hose connecter on it

re-die your threads on the tester, replace 0-ring for sealing

use long 14mm thread, with rubber hose ext, short threads don't "catch" properly