Okay ppl"gotta a 90 iroc 350 tpi"and just bought it.problem I having is that smetimes engine lite comes on"wen it does smetimes"now jst smetimes "uh when I push hard on gas the vavles rattle?now smetimes it doesn't do it when the service engine lite cmes on!but smetimes it does"I'm attemping to take to buds shop if I can catch him there wen lite comes on so we can hook computer to it!but does anyone have any idea why when then lite cmes on n the valves rattle n smetimes it doesn't? Could it b 2 diffrent things going wrong wit it at sametime?

It sounds like someone else may have already adjusted the timing, or modified the EGR system in some way, so you want to figure that out first.
Pull the error code using a paper-clip. Instructions for retrieving error codes and interpreting them are on this site.

You want to figure this out before messing with other things in a quest for more power. It needs to be running correctly first.

Wats it mean pulling codes wth paperclip?

use a paper clip to jumper the aldl pins a to b . this will put the ecm in diagnostic mode and the check engine light will blink the codes.

http://www.google.com/imgres?q=aldl+...d=0CNsBEK0DMCM

Srry buddy but u lost me there lol I nothing of this motor

I included a link for you to read the instructions on retrieving obd1 codes.

Funny now no engine lite n no vavle rattle since bout 20 miles now"wtw any ideas?

Like sbc305 said, maybe you should check your stored codes and disconnect the est and set the base timing. I do not know if you are trying to describe pinging when you say valve rattle.

K

I been having the same problem the car is running perfect, but if i go long distances the check engine light comes on. Thanks for the link tunedperfomanc this is going to help me

np xknightriderx24 if you need help with the codes let me know !

Thanks very much i appreciate that. I'll let you know.

-tom

A paperclip is used as a jumper wire.
When I say " instructions can be found on this site ", it's a hint to use the search feature to find the instructions, as they are already written out for everyone to use.
People here don't mind helping others, but you are expected to do some reading. After all, it's your car.

Checking codes:
https://www.thirdgen.org/service-eng...ht-error-codes

Checking/setting timing:
https://www.thirdgen.org/good-timing-reading