2003 Chevrolet Trailblazer 4.2l

[Crmzendrgone]

do yourself a favor and find someone with a scan tool. a failing part will not always trip the SES, but a scantool will find it. had a car in the shop one time with a stumble and no codes. put a scantool on it and commanded the egr open and closed with no change. we pulled the egr and commanded it open to 100% with the engine off. anything past 60% and the egr would snap shut, yet the pcm was still reading it as open at the value we selected.

Good deal, I will see if my "buddies" will throw me a bone or not.

[hotrodpc]

What about timing belt/chain? How many miles since that was replaced or how many miles does it have on it. Check your plugs and wires. What about distributor,rotor button,PCV valve and dirty fuel injectors. Try pouring some fuel injector cleaner in your gas. map sensor too. Your egr valve might be leaking too. Check for vaccum leaks,

Its an inline engine. Most inlines I have seen are gear to gear timing, without a chain. And as Dragon mentioned its a no dizzy. Have you ohms tested the coils Dragon? It could be a coil. But as Muderator suggested, a GOOD scanner should detect it.

[Crmzendrgone]

No I did not ohm the coils I wouldn't even know what the specs would be. I don't think it is gear/gear. The Jeep 4.0L is a chain.

[mudseeker]

timing chain.............

[Crmzendrgone]

Yes score one for me knowing a little something. You'll have to excuse me I don't get very many "Told you so" moments so, please let me have my moment

[mudseeker]

seems to be a DOHC with 2 intake and 2 exhaust per cylinder.

[Crmzendrgone]

I'll agree as wide as the head is.

[hotrodpc]

Yes, I thought of that after I posted it and was getting ready to leave the house, that is likley not going to be Gear to Gear. As many inline 4 cylinders are not either. I am still in the olden days of Chevy, Ford, Dodge Inline 6's. I really believe that also has a little to do with their longevity and not being able to kill them, as in the Chev 230, 250, 292 etc, Ford 300 and Dodge 225 crooked 6. I have not done any research on those inline 6's in Envoy and Trailblazer, but when they first came for the first year, I was working for a GMC dealership and was told the Inline Vortec 6 is a Yota motor originally. How true, I dunno.

[Crmzendrgone]

Um makes me wonder. Seems like cr'ap like I said I am not a fan so far.

[mudseeker]

not a fan of the 4.2?? seems like a peppy engine to me. could easily take my 5.0 down the 1/4 mile, even if you weighed the trailblazer down to make it fair.