1995 Blazer hard start/Rough idle

Well my blazer only has 84K on her and she has been doing this for almost a year now. After reading the forum I went out and bought a new EGR valve. But, even after cleaning the passage and installing the new unit (with new gasket) the problem has moderately improved but not been totally resolved. I still have a rough idle and get the dreaded P0300 code whenever i let the truck idle for more that a couple of minutes and it will flash the CEL if i dont rev up the motor to "flush" out the raw fuel from the exhaust. I found some advice on the CPI unit here...
http://www.asashop.org/autoinc/feb2000/techtotech.htm
As reccomended, I removed the IMTV to inspect for "washing" inside the plenum. the conditions were this.. having just returned from my daily commute (10-12 miles in traffic and engine at normal operating temp) i saw that the inside of the plenum was wet (seemingly quite wet)? Then, with the IMTV still out i turned the key ON but DID NOT start the engine and saw a cloud of mist come out of the IMTV passage. I know that the fuel injector is supposed to be pressurised by the fuel pump and the fuel injector is supposed to vaporize the fuel but i am under the impression that this should only happen within the confines of the cylinder and not take place in the plenum? I also notice that they truck will start perfectly when i allow it to sit for a couple of days (at least 2 or more) i assume that this is because the raw fuel has evaporated and now it isnt "rich" (basicly flooded). Now that winter has set in i am noticing that my blazer is missing much more when cold in the morning, after the engine temp starts to rise the miss goes away and the CEL will sometimes go away. She will also idle rough at every stoplight that i stop at unless i put the tranny in neutral and rev the engine just barely above idle. I have already replaced the TPS and the MAP sensor so i am fairly sure those arent the problems. I suppose i am still wondering if there should be any fuel related moisture in the plenum and if not should i replace the entire CPI unit or jsut the regulator or maybe the nut kit?

I know there is a wealth of knowledge on this dam vehicle out there and i am begging for some advice.

Its definitely the CPI. I couldn't find the regulator when I did mine, and frankly it's just not worth your while. A "kit" can be had off ebay that includes factory redesigned CPI + nut kit + o rings + gaskets for $400CDN shipped to Calgary, Alberta. No way should there be any fuel in your intake manifold, and if you saw a mist come out of the IMTV upon key on then you definitely have the problem (like every other 95 owner).

There's tons of info and pics on how to do this job on this board though. Just check the FAQ post and use the search button. It's really very easy on a 95. You may want to think of replacing your cat soon after your CPI if you're misfiring already.

welcome to the board.
here are the part #'s for the cpi and nut kit (just in case)
The CPI unit gm part # is 17113673
The fuel lines, called a "nut kit" are # 17112705
u will also need a new upper intake gasket for the swap which is about 11.50 (fel-pro) at advanced auto parts. brilo pads work well to clean off the old material. good luck with the swap; not to difficult at all.

This is where i was heading but i needed some validation. Thanks folks, i really appreciate the advice and i will use those part numbers. An E-bayer named texas-auto-parts has the GM redesigned CPI unit and mentions 'kit' in his description but i cannot be sure so i jsut sent him a message asking if that comes with the fuel feed and return lines so i can be sure that i dont need to order the nut kit with the CPI. His price is 259.99, here is his ad

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=8022654676


Thanks for having me!! i have been reading this fourm since i bought my Blazer and had to figure out how to reprogram my keyfob... if anyone wants to know send me a msg,

Welcome to the Board.
I have to agree with Cailen. It really sound like your CPI needs to be replaced. Here is a excellant link on step by step CPI replacement.

http://www.automotiveforums.com/vbulletin/showthread.php?t=473110&highlight=cpi

E-Bay Parts
http://cgi.ebay.com/ebaymotors/OEM-Fuel-feed-and-return-hoses-nut-kit-4-3-Chevy-GMC_W0QQitemZ8022654090QQcategoryZ33554QQssPageNam eZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/ebaymotors/NEW-CPI-4-3-W-Fuel-Injector-Spider-S-10-Sonoma-Vans_W0QQitemZ8022654676QQcategoryZ33554QQssPageNa meZWDVWQQrdZ1QQcmdZViewItem

Wow, that is the best pictorial of CPI injector replacement that i have ever seen!!

THANKS a big ol bunch!! I have to wait until after the holidays to buy my new CPI since Christmas has wiped out my "fun" money. *yeah... real fun replacing the CPI...* but alas, i this isnt a inexpensive repair and i would rather do everything all at once rather than have to go back in there again.

You guys ROCK, thanks a million!

Hey Gabe25...

My blazer is a LS model that has the body side moldings like the "lifted" one that you have in your "fleet". Currently they are showing thier age by starting to peel and crack. I was wondering if you know of a place where i can get replacements? Or... would it be possible to just remove them and clean off the adhesive and just do without?



BTW.
I am sure i have a fuel leak now, those pics show that the passenger side is filthy and mine is rather clean. That has to be from fuel being sprayed from the failing injector..

Appreciate all the threads, this site continues to save me huge amounts of time and money, towards maintaining my 1995 Chevy Blazer.

Much Thanks.

Bought mine off ebay from this (http://cgi.ebay.com/ebaymotors/4-3-FUEL-INJECTOR-SPIDER-S10-BLAZER-SONOMA-PROKIT-1088_W0QQcmdZViewItemQQcategoryZ33554QQitemZ802139 3096QQrdZ1QQsspagenameZWDVW) guy. Best bang for your buck. I ended up using fel pro gaskets though.

Get this fixed ASAP, don't delay, every mile you drive like this is death to your engine and bearings.

The fuel is going into your oil and destroying your bottom end.

OK, so i am going to replace the CPI unit on my blazer but i need one more peice of information...

What are the torque specifications for the upper plenum?? I dont want to warp that thing when i reinstall it.. I dont want any air leaks either.

OK, so i am going to replace the CPI unit on my blazer but i need one more peice of information...

What are the torque specifications for the upper plenum?? I dont want to warp that thing when i reinstall it.. I dont want any air leaks either.
pic up a hynes or chiltons manual.

pic up a hynes or chiltons manual.
D'OH

D'OH

124 in-lbs.

YOU DA MAN. thanks, i think you can get factory service manuals from helm.com

here is the link

http://www.helminc.com/helm/welcome_select_oem.asp?Style=&mscsid=MJ3TWLCPEH8F9N9EUJHF5NU9WFKQ6DXD

they arent cheap but try to buy one from the dealer!

ebay too , much cheaper.

[QUOTE=dirtnap300]Hey Gabe25...

My blazer is a LS model that has the body side moldings like the "lifted" one that you have in your "fleet". Currently they are showing thier age by starting to peel and crack. I was wondering if you know of a place where i can get replacements? Or... would it be possible to just remove them and clean off the adhesive and just do without?

++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++

The molding can be removed. I did it to my 97 S-10 Pickup. Tried to give it a clean look. It wasn't to hard. Just be careful when removing the molding you don't scrach the paint. I just use gas to remove the adhesive and gave it a good waxing. As for replacement molding. You'll need to search around. I normally don't replace the molding.
http://i32.imagethrust.com/t/98623/joshua.jpg (http://i32.imagethrust.com/p/98623/joshua_jpg.html)