The problem seems to act up especially in cold starts ( not driven in a couple of hours). I open the door and notice the interior lights come on, so i know i have power in the battery....(note: i have changed the battery, starter, and alternator in the last month), i proceed to put the key in the ignition and turn it....sometimes it makes a clicking sound (not a starter clicking sound) and then it will start, sometimes i get nothing like i dont have a battery hooked up, and sometimes it turns and turns over before it cranks. I notice it starts right away when i try to start it after i just drove it....and sometimes it cranks over and over before it starts. I am thinking i have a electrical problem in the ignition switch or my tumbler is bad, or bad fuel pressure ( but when its on its drives perfect), or bad ISC....it has 190,000 miles and it is a 93 seville sts and also the owner before me has a speaker amp hooked up to the battery, but it only powers the inside speakers i dont have any fancy subs or anything. I am also thinking since its a side post battery the way he has the amp hooked up is through and extension bolt on the positive terminal BEFORE the positive cable to the starter, etc..... so maybe the amp is drawing power before it reaches the positive cable?!???? i dont know but when the car is on my voltage reading is 13-14 volts so im good there. Any advice would be gratefull.

 

Disconnect amp and see what happens. What is tumbler? Check fuel pressure, should go to 38psi+ and hold soon as key is turned to run. If fuel pump relay circiut isn't working, engine would have to crank till oil pressure built up to cause oil pressure switch to supply 12v to fuel pump. Check for codes also; cam or crank sensors could cause condition.

 

i believe the problem could be a bad negative battery cable or positive battery cable.