I have a '95 Blazer, 4.3L Vortec 4x4 with 144k miles on it. Yesterday, it started to chug. It didn't stall at all, though. I just replaced the fuel pump, screen, and relay on it a few weeks ago, and the CPI was done six months ago, so I know that's all fine and dandy. I heard that the chugging issue can be because of a crapped out CTS, but I'm not sure. The exhaust fumes smell a bit rich too.

Any advice on this?

 

Check timing advance,what brand pump did you install. Hopefully you didnt install a aftermarket and went with ac delco.....these blazers are PICKY

 

Since I couldn't do it myself (college hogs my time up), I dropped it at the shop. I'm not sure if they used an OEM pump or not. The good thing is that they guarantee parts and labor for a year. I'll see if I can put a call in and ask.

 

Have them check the pressure for you. If they say "oh its not that" have them do it anyways,better yet have another reputable shop do it for you incase the place you had it done says its fine to get you outta the way. Fuel pressures important.

edit,realized you had a cpi motor. Stop by autozone and get the pressure kit. Its free to loan,BUT you have to leave a deposit just incase you never return it. I think its like 150.00 deposit. but remember as soon as you return it you get every penny back.


Look in the book it comes with and find the fitting # you need for the kit,install that fitting on the pressure check line and hook it up to the fuel nipple on the engine (i think its near the center,near the firewall. you'll see a black cap on it.

Now,turn the key to the on position (the spot right before you turn it to crank it). Look at the gauge. it needs to be above 58ish psi (ideal is 60 or more) and hold above 55 for 10 minutes. If it does,everything passes. if it falls below 55,check it at the inlet of the fuel filter on the chassis. that way if it fails pressure there you know its the pump and not the fuel regulator. If it passes as the fuel filter,and falls at the engine,its the regulator or leaky injector. All this is easy,takes maybe a hour to do everything,15 minutes to check just the nipple at the engine. that'll rule out fuel pump/fuel regulator issues.


Also...ha...so much to think about...but pickup a can of Maf cleaner....if they try yto sell you throttle body cleaner,or carb cleaner tell em to work at mcdonalds. It must be maf cleaner...anyways.....clean the maf sensor. (silver lookin thing that is between the air filter box and the throttle body). it'll have a screen inside it. spray that screen down real good with it. dont scrub it. just spray it. let it dry and test drive it. alotta times they get dirty and can cause all kinds of issues.


might as well throw this in...

Clean the egr valve. its underneath the throttle body. round lookin thing with a wire on it. remove the connecter,the 2 bolts and remove it. you'll see a little piston lookin thing that moves in and out when you push on it. Get some brake cleaner and spray it on it and scrub everything with a toothbrush. reinstall it and drive it and see if anything improves.

 

chris015: Thanks for the tips! I'll try cleaning the MAF sensor and the EGR valve, and see if that helps. If not, then I'll get the pressure kit. Also, since I did the pump and relay, I've been running 87 gas. It's at 1/8 tank now, so I'll throw some hot gas in and fill it up with high test, and see if that's an issue.

 

Do not put anything other than 87 octane in the tank. That is what the engine requires.

 

chris015: I checked the throttle body, and it's sparkling clean, surprisingly. Next, I'll check out the EGR and see if that needs to be replaced/cleaned. It still chugs, but never stalls out.

LannyL81: I filled the tank with '91 octane', and it ran fine, minus the chugging issue.

 

Don`t let the gas get that low in the tank, you`ll burn out the fuel pump.........

 

UPDATE! As of right now, the Blazer runs fine. Very minimal sputtering. That's it.

 

My '95 S10 Blazer doing the same thing. It seems like it only do it the first run of the day I am getting tired of this and wish I know what to do.