92 q45 knocking, need needs on it

[dreadedboost]

I have a 92 base model with 126k, i was doing the under plenum hoses and new injectors and after i got it all back together it ran 10x better than it ever had before, smooth power and no more rough idle. well that lasted about 1 day of driving then i was at a stoplight and the idle dropped to about 200-300 and became terribly rough obviously and wouldnt even try to accelerate any, i had to get it out of traffic. at the same time it makes a hard tapping noise. i believe it is coming from one of the heads, possibly a stuck valve or thrown rocker arm. any ideas?

[gniknave]

Sounds like a chain guide problem. Best thing to do is not drive the car (obviously), don't panic, and read some of these threads and see what you think you should do.

http://nicoclub.com/zerothread?id=25201

http://www.q45.org/guidereplacement.html

http://www.nicoclub.com/zerothread?id=92729

http://www.nicoclub.com/zerothread?id=92729

[dreadedboost]

i guess i should mention this now, but after i parked the car and it was still running it stopped the super low idle, now its just a little rough

[gniknave]

Do you still hear the hard tapping noise? From the sounds you described in your earlier post, it seems that one of the guides may have broken, tangled in the chain - causing it to skip a tooth, and then the guide piece may have come loose and fallen into the oil pan. I guess that's worse case scenario. Be on the safe side and have it checked out before you drive.

The last time I JUST had a rough idle, it was because my EGR connector was loose. I took the connector out and cleaned it and put it back on. It worked fine after that. Of course I didn't have any tapping first.