Got a question for you~ I have a '95 Blazer that is a dream. The only weird thing that it's doing is missing. I drive it every day, and every day, when it warms up to 200(?) it starts to miss and buck. It's only for about a mile at 55~60, but I'm at a loss as to why. Lately, since I've been home during the break, I've noticed it even more-so at 30 MPH. It's only for a short while, but it freaks me out! I think if I had my daughter with me and it broke down in the cold, I'd be pretty (upset?) If anyone could give me an idea as what to check, I'd love it! Fuel filter??? The "check engine light came on~ I had it checked at a FLAPS. It said it was in the fuel system. (one of 4 things) (?) Pump, filter, regulator, or injectors. I dumped a bunch of cleaner in it. That knocked out the idiot light, but didn't get rid of that chugging during mid-warm up. I KNOW I'll never talk to y'all about this when I get my 52 rolling! Fuel pump??? Thanks in advance! BTW~ Big Brother chased me back to my home site with this question. It was dangling out there in the '95 site for way to long. He figured you guys could help me out better than (whoever) is out there for the later models. Computer CRAP!!!!!!!
Zig, do you know exactly which codes were pulled? It may help quite a bit. Also, if you accelerate wwhen it is missing, does it get worse, better, or stay the same. Any loss of coolant for no known reason? Just trying to gather more info, to better pin it down.......Mike
Thanks, Mike! I'd have to check with the guy who checked it for the codes~ if he remembers. When it started chugging around here the other day, it did seem to get over it quicker when I got on it a bit. Maybe I can pull the filter today and see if it has any obvious problems.
Missing To follow up on where I *think* Bruce is going , some of these engines have a TPS Switch and it tends to wear out in one particular position , where your throttle is 90 % of the time ~ This is a SWAG so pardon me if I'm off base here but that's the first thing I'd swap out using a junkyard part... " A Mister , A Miss A Car , A Curve - He kissed the Miss and Missed the Curve "
Throttle position sensors Zig, when you go back to the FLAPS to see about your code, if it is a "P0123" chances are good that it is the TPS. Visually inspect yours to make sure the the connections are good.
Guys~ my Blazer doesn't have a tac, so I'd be guessing at the RPMs. The chugging starts as it warms up to @150 degrees, and lasts until the thermostat kicks in. The chugging at 55~60 doesn't last as long or is as noticeable as it is putting around town. It seems to idle OK at stoplights. It was just weird that the check engine light would go off after I feed it some fuel system cleaner. It would probably take 20 or so miles to get it to go off, but... Anyway, thanks again for any ideas. I appreciate them all. Good news~ instead of working on my Blazer, I've pulled more stuff off my 228!
Stupid Question , 'K ? You DO have a 190° or hotter 'stat in it , right ? I wonder if it's stuck in " open loop" ? Could be as simple as a dirty Oxygen Sensor too , those go bad every 50,000 miles or so , it's amazing how much better most engines run after replacing them .
P30300 Multiple random misfires - random cylinders. Probable causes 1. Ignition system fault - spark plug(s), ignition wires, coil 2. Vacuum leak 3. Injector fault 4. High or low fuel pressure *No, I did not suddenly become a gifted mechanic, I just thought I'd run it back into a flaps just in case my idiot light was "out". It was. So this is the scoop. Apparently it's running rough most all the time~ I just notice it more during that specific time. I would have posted this earlier, but I just couldn't resist pulling more stuff off my block! All I have left to take off is the radiator and hoses. It looks like removing the hoses from the heater will be a simple case of cutting the old ones off at the firewall? Anyway, thanks again for the help with this. I guess I'll have to drive the Jeep until I get a chance to look at things more closely...
is it a vortec with multiport injection, saw this happen on a astro van, turned out to be the "spider looking" injectors in the intake, they are bad about going out, if you have to replace one, replace them all, but the more I think about it, it was mis-firing on a specific cylinder, so dunno?
228 Fixin' Yes , all you needs do is : loosen the hose clamps until you can _gently_ work them loose and slide down the hose and away from the firewall , then slit the old stiff hoses using a new blade , then every so gently peel the slit ends away , DO NOT pull , twist or yank on those hoses ! that's the # 1 way to create heater core leaks . -Nate Zig Wrote : All I have left to take off is the radiator and hoses. It looks like removing the hoses from the heater will be a simple case of cutting the old ones off at the firewall?
Zig, Is the check engine light on all the time now? Had this problem with a 20,000 mile truck -- thought it was a bad o2 sensor but the codes indicated a leak in the fuel system -- turned out to be that the gas cap was not sealing properly and setting off the light. Make sure the gas cap clicks a couple of times when you put it on. A new cap and 15-20 miles cured the problem-- too bad the new trucks can't be as simple as our ADs. I know it sounds crazy but it is worth a try.
Zig, bummer. P0300, is one of the pretty generic codes. It simply indicates a misfire that is not repetitive enough for the system to identify which specific cylinder is causing it, or there is something wrong enough to cause random misfires so it can't isolate it. That being the case, I would check for vacuum leaks. Check around the intake, vacuum hoses, etc. using a carb cleaner spray, or similiar. Listen for a change in rpm when you spray around. If you spray at a vacuum leak, rpm will either go up noticeably, or possibly drop drastically. Depends on size and location of a leak. Don't spray onto plug wires, or distributor cap. It could potentially cause a fire. If you don't find anything there, check the distributor cap and wires for signs of damage. You are likely looking for something that can affect all the cylinders, rather than one specific one. Things like vacuum leaks, bad cap, bad TPS, EGR stuck partially open, low fuel pressure, are just some examples. What engine does it have. Those vehicles have a pretty primitive engine control sytem compared to todays vehicles. The check engine codes usually set based on symptoms caused by a problem, more often than by the problem itself. It may have to get worse, or need a scan tool and a technician with some knowledge before it gets fixed. Keep giving us info though, and we'll do our best to help.....Mike
Thanks again, guys, for both bits of wisdom. It is a Vortec engine. (primitive engine control system compared to today? YIKES!) All that hoop for a quick start and 18 MPG... As far as the light staying on all the time, I don't know. Apparently it (the light) went out a while back. I was hoping that was the case. I'd hate to think it could act like it does without the idiot light coming on saying, "Yo, P~ I think there's a problem here." Anyway~ to drive it until this weekend, or just let it sit. I guess I'll let it sit 'cause I'd hate to have it break down in the DARK morning hours of my commute. Thanks again, all!
Sorry I hadn't been on for a while but here's my input on your situation Zig. If this problems occurs at steady throttle more and can go away when giving it gas it is most likely not a fuel related problem. If it were fuel related it would be dead opposite because the engine would be starving for fuel. Check first things first. Check for vacuum leak with brake cleaner. These engines are notorious for intake leaks. Also check your plug wires for wear such as tracking marks or corrosion. If it were me I would probably take the EGR valve off, take it to a work bench and bang it on the bench pretty hard (mounting surface side to the bench) to see if any rocks (carbon build up) comes out. Also look down the EGR holes to see if you have any carbon build up. If so then you will need a new EGR and an Induction flush. Your local dealer could flush it best if you don't know how. Also another tell tell sign of an EGR problem is slight acceleration misfire when going up a slight hill, usually around 1800-2400 rpm. Also the TPS sensor is another good idea, but it will always set a fault for it, so I would check elsewhere first. If it were injectors then you would probably have a hard start or cold rough idle so I would still check out other things before diving into the injectors. I really hate that it only give you the generic PO 300 fault cause it's hard to diagnose without putting my hands on it, but check out your wires and plugs, I don't remember it it has coils or a distributor, if coils check for corrosion and white tracking marks, if distributor then check cap rotor and button. Don't rule out the ignition module in the distributor as well. Also if its distributor you may need to check out the bottom of the distributor for play, I've had this whip my ass before, but check other things first. Hope all this helps, keep us updated on what you find. I'll try to get back on here more often, I've missed you guys I've just been distracted with other things.
THANKS KEVIN!!! Wow! Great to hear from you again! If you're like me, not being able to get to this site is tough to do! I greatly appreciate your ideas~ it gives me a lot to think about! The Jeep had a low tire yesterday morn, so I decided to try another round-trip with the Blazer. Same thing. Until the temp gauge starts climbing, it's fine. Then as it gets warming up, the problems with noticable misfires becomes more pronounced. It isn't until the temp gauge shows the thermostat opens that things mellow out. In other words, once the engine is good and warm, the problem really isn't even noticable. This makes me think it is an intake leak? Things expand with heat and maybe (if you're talking intake manifold leak) the expansion knocks out the extra airflow causing the engine to "smooth out" ???? I'm not sure about how you check vacuum leaks with brake fluid though. Best I could tell, it does have a distributor. This weekend, I'll pull it into my dad's garage and check what I can~ we'll see... Thanks again for the great advice, and Kevin, I hope the distractions are great ones!
Vacuum Leaks You use Aerosol Brake cleaner or Electro-Contact Cleaner , NOT brake fluid ! . DO NOT use carby cleaner nor WD-40 as both of those cause rubber bits to rot , seals to fail etc. . Back to the test , affix the plastic snorkel and spray along the various joints and gaskets with the engine idling , I like to load it by leaving in gear , wheels chocked , if the engine begins to stumble or speeds up suddenly , you've found the leak ~ you can try gently tightening the fasteners near the leak but be aware that the seal is compromised and must needs repairing , sometime a gentle twist of the bolt will allow you to drive it a bit longer until warm weather appears . Good luck hunting and let us know what you find .
You scared the sh!t out of me, I thought I told you brake fluid, but I went back and read my post. Whew, what a mess that would be. Still could be carbon in the EGR system and this is how. As the engine is cold the carbon hardens and causes the EGR valve to not open properly. More heat then the carbon softens and the EGR works fine. Just food for thought. Distractions here has been a lot of holiday travel, and work schedule changed, work more pay you less kind of thing. So the truck has set for a while and when I'm home I'm exhausted so I don't do much around the house. Oh yeah and a five month old jack russel will keep you VERY busy. So not real bad destractions, just destractions. But the first of next month kicks off hot rod season, big swap meet here in Nashville.
You help me~ I'll help you! Who needs that kind of help, though?! Thanks again, Kevin. That makes absolute sense to me, and now I can't wait to get my manual and find out where in all that (stuff) it is! Plus, I'll have a good excuse to invade my dad's garage! I'll get to this this weekend, and let you know how it turns out. I just hate giving up "work on auto" time for something other than my G... Ya gotta do what ya gotta do though, right? Kevin~ when you can get back on here, there are a couple(?) of new faces here that are doing the S10 frame thingy. I know you will be able to help them out with that, also! Thanks again, all!
I've replaced many sets of intake gaskets on the 4.3 engines. A few on the full size 5.7 blazers as well, but the s-10 are more common. A lot of people don't recommend the GM replacements either. Go with the newest design fel-pro. You can see the problem after removal, chevy made the "gasket" out of a strip of rubber sandwiched between plastic. And a personal recommendation, Get rid of the dexcool antifreeze, its very corrosive after a couple of years. Alot of times you can associate the intake gasket problem with a slow mystery coolant loss. Just some thoughts, hope you have luck diagnosing it. Spray along the bottom of the intake runners and you'll probably find it.
