First off I'm new here & hope to learn more about Blazers. I have owned a Trailblazer. We just bought a 1997 Blazer 4x4, 4.3L, with only 87,000 miles. We have a problem. I was driving it home from 150 miles away where I bought it. About 40 miles down the road the service engine light started flashing & the Blazer started missing. I got it home & went to gas it up It got 17 MPG @ 77 MPH over the 150 miles. After I gased it up & got something to eat the problem seemed to clear up & the light went out. This was Thursday night. Well today it started again. This time the light appears to be solid now. Does Anyone have any ideas of what maybe the problem. It can't be anything to serious, it must be a sensor acting up or failing. I have no way to pull codes. I kind of jumped the gun I just did a search Sorry I jumped in before searching. Does AutoZone do a scan for FREE?
Thanks,

 

Flashing CEL (check engine light) is an indication that there is potentially harmful detonation occurring in the motor. If the CEL is solid, that means that there are stored diagnostic trouble codes. The first place to start is with seeing what the code is. I'm hoping it is more than just a P0300 code just to give you some more direction.

Yes, Autozone, Advanced Auto, and quite a few other retailers do free DTC scans.

Once you know the code(s), we can help further. Another thing that you may want to do is a full tune up consisting of plugs, wires, cap and rotor. Also, clean the EGR valve (new gasket) and the MAF sensor with sensor safe carbon cleaner.

 

WhThanks for your response. I went to AutoZone this AM and it brought up a P305 code, only code number 5 misfire. They gave me a print out. From looking at it I think it is a plug or wire. I just bought this Blazer & really like it, The first time this happened it was after the dealership pressure washed the engine to clean off some anti-freeze when they changed the thermostat out. The second time it happened I was washing off the underside of the truck, skid plates engine oil pan & suspension. So from that I asumming it is a bad plug wire that is affected when water get to it. Any input would be greatly appreciated. Thanks

PS what is the ohm resistance for plug wires? To tell if they are good or not?

 

Is anyone out there? What I found to this point was a definite #5 miss fire looking at the plug. discolored but in good shape. Had to order plug wires will be in tomorrow. I checked the ohms on the #5 wire it read .886 so I checked #1 wire a little longer an it read 1.468, so unless I'm in left field I would have to say the #5 wire is about done. The truck is back to running OK service light is out, but anytime water is introduced it acts up. Both happenings were after water was used to clean. As soon as it dries out everything is normal. I live in Arizona so we are dry for the most part.
Thanks

 

Sounds like you're on the right track. You can always tryone of theeasiest tests in the book...wait until dark andspray water (light mist, not heavy stream) along the wires. If you have a moisture induced short, this shouldshow youwhere it's at (look for sparks and listen for a ticking sound).The distributor cap and probably some of the sensors can be sensitive to moisture, but I don't believe they would be specific to any one cylinder.

Your resistance readings don't necessarily tell you anything in this situation. The core of the wire can be good when measuring the resistance end-to-end, but the bad spotin the insulation will allow the electrical current to short to somewhere on the engine before it reaches the spark plug. Moisture improvesconductivity which exaggerates the problem.

 

Yea, your right. I just know that if my memory serves me these new trucks have plug wires with a fairly high risistance. under 1.000 is pretty low.

Thanks for the input.

 

Have you pulled the distributor cap off yet?

Distributor caps are not water proof, not even water resistent, they are subject to cracking and both will cause missfires especially when wet.

Ihighly recommend you use good quality plugs, plug wires, and cap & rotor. These are not some cheap **** engines, these are highly tuned monsters and need quailty products. The chepaer crap don't alst and will leave you scratching your head swearing up and down that you just rplaced them and they aren't the problem. Don't believe me, search the forums for P0300. The Death Code!

 

Yea, I'm an old school mechanic that retired from being a mechanic in 1984. Cheap parts didn't work on old school stuff either. I replaced the wires with a set of (NAPA 5yr) I replaced the #5 plug wiith the OEM AC. That made all the difference in the world. New wires have as I checked around 7.65 OHMs of resistance. The factory wires that were on there, varied from less than 1 OHM to aroun 1.6 OHMs. So a wire carbon, or not that has less the 1 OHM is about an open wire. All the plugs I checked looked good .060 gap & clean very little sign of wear. I haven't touched the cap & rotor, for now I convinced the wires were the main issue. It runs out great, NO service lights, No sputtering at idle, So I'm going to run it for now. I will change the cap & rotor at a later date as just a part of my normal PMs.
Thanks to all who have thrown their thoughts & ideas here. I will be sticking around the forum, it is a great place to learn about our new to us Blazer. We both really like it, & are sure it will give us a lot of pleasure.

 

Sorry I didn't reply right away. I typically get an email of all of the posts made on the forums and that hasn't been working lately. That coupled with a VERY busy past few weeks at work and I don't have much time during the day to check up on here.

Glad you got it all figured out!

 

Hello I am new here. I just bought a chevrolet Blazer LT 2000 and I have a problem. It's always a light (service 4WD) appear on my dashbord and I can't switch the transfert case. Is there anyone can help me thank you