A couple of months ago my wife bought an automatic 93 Z28 V8 350 for $2200, a seemingly good deal. So far, we have replaced the starter, the water pump, the TPS, the alternator, the A/C compressor, and the plugs and wires. When I pulled the plugs they were pretty much destroyed (completely black with no core). I replaced them with Autolite Xp Iridium/Spark Plugs and Duralast wires, now the car sputters at higher RPMS.

My question now, is what could cause this? I'm still pretty new at this but I gapped all the plugs to .05 like I was told they should be. Could there be any other causes? Any help would be great.

Also, I would like to upgrade everything. I was told I could buy a new 350 for under a grand and build up the engine from there. Where could I buy this from and what would you guys recommend be done to make this car worth keeping?

 

Not sure about being under a grand, but I've also thought about dropping a new engine into my 94 down the line. I've found crate engines for around $3500+ but nothing as low as what you have told. hawksthirdgenparts.com is a pretty good source I think, take a look around there.

 

I'm just looking for the small block or is it short block? I'm going to use the same throttle body and headers if I have both. I really know nothing about cars ha ha. I figured get on a forum would be better then listening to people I know.

 

Get it running correctly first.

Scan it for codes:

http://shbox.com/1/dlc2.jpg

Check the fuel pressure.

Check the ignition control module (ICM) and the coil.

Clean the injectors.

 

Yea, I just joined this forum in March being in the same boat hardly knowing anything. These guys give great input and have helped me out quite a bit when I run into things I have trouble with and such. Another good site linked to this would be shbox.com(shoebox's site) I believe he's a moderator with this forum and his site is extremely helpful as well.

 

The check engine light isn't on. Would there still be codes?

How do I check the fuel pressure?

How do I clean the ICM and coils?

I'm working on cleaning the fuel injectors.

 

Go to the shbox.com site we posted.

 

There are codes that don't cause a light....you still have to check for codes.
You don't clean the coil and iCM? You have them tested. Shbox.Von and autozone can help...

 

That makes more since I thought it said clean. I'm about to have someone put seafoam in the car to try that.

 

I install ngk copper tr55 spark plugs. I have always had good luck with those. Also you said you installed a new water pump, I take it the old pump was leaking? If it was i would imagine from personal experience that it leaked right into the opti since thats right behind the water pump. Is the ses lamp on at all? Change the fuel filter and check the fuel pressure at the rail.

 

The water pump had a blockage and caused some problems. But i think my car has a coil and not the opti? (i don't really know) No the ses lamp isn't on. I wish it was... or and also when i get over 2000 rpms the gauge drops to zero.

 

Your car has BOTH an opti(distributor) and a coil (located with the ICM, ignition control module). Any simple reference information such as where parts are located or maintenance can be found at the site we've been listing above. Go to shbox.com and have a look around at all the available information and you'll see what we're talking about.

 

Already answered that question - when you ask a question, you have to go back and check to see if its been answered.

https://www.camaroz28.com/forums/sho...9&postcount=38

When you get over 2000RPM, WHAT gauge drops to zero?

 

The RPM gauge drops to zero when I get about 2k rpms

 

OK.... that's called the tachometer.

The 93 is different that any other year of the LT1, in that the tachometer is driven off the coil, with a filter in the circuit. All other years get the tach signal from the PCM (computer). If the tach is failing at 2,000RPM, could be the tach itself (swap in a different instrument cluster) or possible the filter.