03 Trailblazer rough idle

[da98ace]

2003 trailblazer wont start when tempture is below 40 degrees has new battery and startes as soon as jumper cables connect and remote doesnt work when it is below 40 degrees

[ProTech]

You answered your own question, LOL! Whether you think the battery is good or not, if it starts fine when you attach jumper cables, then you DO have a bad battery. Replace the battery and you should be fine.

[Lauren]

I was driving on the freeway and out of nowhere the truck just revd up reallly high and would not let me engage with any gears at all . Coould this be an electrical shift module ?

[ProTech]

This could be something like a transmission slipping if you are unable to get any forward gears to function properly. If the check engine light came on, then a code has set that will help in diagnosis of your Trailblazer. Usually, they don't see many trans problems on your type of vehicle, but you never know.

Other possibilities could be a throttle body that has either stuck or broken. A vacuum leak can cause an excessively high idle and revving. You could have a different sensor on the truck that has malfunctioned, or even something like a faulty computer.

A qualified service shop or dealer might be in order to get it properly diagnosed, especially if it is a transmission problem. You don't want to waste a lot of money trying different parts on a problem like this.

[Lauren]

Thank you very much Thats whyI'm thinking the tranny is just toast or something because it doesn't have a code And I just did spark plugs and wires at home and it was running really good also could it be a bad shift solenoid . I'm sorry for all the questions I just want to get the closest answer so i can fix it myself . I am kind of embarrased to ask , but i'm a young mechanic and i went to school for diesel so I'm not 100% on all this . Thannk you again though for the response back that does help narrow things down a bit .

[ProTech]

I wouldn't think it is just a bad shift solenoid, but it's really hard to say without working on it myself.

We are here to help, please feel free to ask anything! And thank you too!

[chevygal21481]

I have a 2003 Trailblazer LS, 4.2L - 6 cylinder. 191,000+ miles. It has been running rough for a while but just off and on until last Monday. It sounded just awful and was really shaking. My check engine light has been on but started blinking rapidly at me. I took it to have it read and I got the following codes c0237, p0440, and p1345. Changed the fuel filter (it was time to change) and the crankshaft position sensor. Still running crappy and throwing 5 different codes (didn't write them down). Today I changed the spark plugs, they looked fouled and had rust lookin' stuff on the bottom end, I also noticed oil coming from the timing solenoid area so I pulled it and it was gunked up, replaced it as well. Still a no go. It ran a lil' better but still shaking. The check light would come on and blink and go back off so I drove it a little longer still no light, then turned on the air and there it went. Came on and started blinking at me. Took it to have the codes pulled and I only got one p0301 misfire #1. I'm thinking it is just a bad ignition coil in #1 but I'm tired of throwing money at it. Any other ideas than just the coil? Also I had a complete fuel system flush done in Feb. last year. I changed the plugs at that time too.

[carriedi]

well you have done a lot of stuff yourself so try this: take the coil and plug out of cylinder#1 and switch it with the ones in next cylinder over. Drive the car and see if the code moves over to the other cylinder. If it does then yes you probably have a bad coil. If it still stays on #1 you need to look at fuel or a mechanical problem with #1 cylinder.

C0237 rear wheel speed sensor,
P0440 evap
P1345 cam and crank correlation

the only code there that would probably cause an engine problem would be your cam and crank correlation. You should do some checking on your cam sensor. also verify that your crank pulley bolt is tight. (has the crank pulley been taken off recently?)

If there was a big evep problem it could be a problem too, but not usually.