Delphi, which is factory original equipment, (the good stuff) it's under $200 on Amazon, and GM factory labor time is 1.4 hours to replace the injector assembly. That calculates to around $350 per hour labor according to the shop you checked with.

 

Ordered the Delphi FJ10565 Spider Injection unit from Amazon.com. Forum Member Captain Hook says that the GM factory manual says 1.4 hours are needed to put it in. Since my nearby shop wants too much money (and doesn't want me to supply the part!) guess I'll have to find another to do it. Living in Philly PA, I must have a dozen shops that are within 3 miles from home. Don't expect any problems finding one that's willing to do the work. Will update later.

 

So the new spider arrived a few weeks ago. Meantime, my odom showed I'd driven about 100 miles so time to fill up. (gas gauge not working) My mileage improved from 13 to 16 mpg. I credit this increase to the new AC Delco plugs, cap & rotor which made the code go from P0300 to just P0304. That last 100 miles was partly driven with the old plugs (etc) and partly with the new plugs (etc). Being a bit "****" about things, I want to see what my mpg is after a full 100 miles or so with the new stuff. And I don't just want to drive aimlessly to rack up the miles so that I can maintain truly "normal" driving. If I should exceed 20 mpg next time I fill up (with my 80%/20% city/highway driving) that would be great! But it would also make me question whether installing the new spider is warranted. If this happens I may take it to a place that will re-read the codes for free coz having a misfire and averaging 20 mpg doesn't seem probable.

 

I have a 99 Blazer and was acting just like yours. I did the usual tune up using ac delco parts. This did not fix the problem so i ordered the spider unit from Amazon and put it on myself. This really made a big difference in the power, fuel mileage. I will not say it will fix your problem. May, may not, but it make a big difference in my Blazer

 

So I passed 100 miles, filled up and checked my latest mileage. Its back to 13 mpg again - what it was before the new AC Delco plugs, etc. What happened to the 16 mpg from last time? Looks like the new spider injector is next step. Pep Boys Auto tells new they have no problem installing owner-supplied parts. They also advised that I should look for bad/arching plug wires. My wallet's been taking big hits with other issues so I'll have to wait a little longer.

 

Inspect the wires for white powder. That's an indication they are leaking.
To further verify that, spray water mist around the wires at night in a dark area and watch for arcing.

 

The engine began running bad at times on Black Friday (sputtering, threatening to stall at lights, etc.) so it was off to Pep Boys Monday to have them install the new spider I've been sitting on for months. They up-sold me into getting a new upper gasket kit while it was apart. Ok, I guess. They promised to test drive it afterward but they did not. IT STILL IDLED LIKE CRAP. The technician had (conveniently) left for the day and had to be called at home to ask him where the paperwork was after 5-minutes of looking failed to find it. They ran a free complete diagnostic which spit out three trouble codes - none of which was a P0300 or ...04, etc. - and none appear to have anything to do with a rough-running condition.

So I'm obviously p-o'd. They trim some cost off the bill and invite me back on the diagnostic wiz's next scheduled workday.

But things got better!!! By the time I was about a mile away from the shop, I felt the car seemed to have more pep than before. The rough running seemed to have stopped. So I kept driving some more as I seem to recall - either from other Forum Posts or the Amazon Delphi searches I did earlier - that it sometimes takes a bit of time for all of the sensors involved to sort themselves out. I'm going with this theory for now.

I look forward to my next fill-up in hopes that the mpg has improved.

 

Hey Brian5792,

So did replacing the spider assembly end up correcting the issue? Better MPG? I'm unfortunately getting the dreaded p0300 code.

 

Give the guy a break, he's just trying to make his 6th million!

 

My 01 has the P0306 and with the advice of my mechanic he said fire it up after dark and watch for sparks. You have to lift the flaps behind the front wheels to see the plugs. While it was in my garage and dark I started it and watched the right bank where the misfire was and it lite up like a Christmas tree. Getting new AC / Delco plug wires today at advance store, have no idea what the old ones are. They look good but perform bad. Just a cheap easy thought. Also the wire set at Advance runs about $80 but if you run a search on Google for Advance Auto Promo codes and write them down and keep going through the best ones you can order online and pick up at the store. This set with the code will now cost about $52, quite a savings. I have saved a pile searching for the best ones and applying them until I find one. Some work and some don't.