Think I going to go nuts.....

[TBDriver]

Hi all, I have a 2004 Trailblazer 96,765 miles on her.

I wanted to do a full tune up that included:
Fuel filter
air filter
throtle body clean
spark plugs ( AC Delco )
coils

the truck started working fine for the first 250 miles after all the changes, all of the sudden I could be driving in the city area and she just dies on me, (Stalls). When you try to start her back up, sometimes she starts right away but other times She craks but no start. Or she she tries to turn over but whith eather hesitation to the max or like she has a bad miss fire or out of timming. It goes on for a couple of seconds, if i step on the gas eather she comes out of it with no codes or no "Check Engine Soon" light, no "Reduced Power" light. Or she just stalls again. going throu the same proces till she comes back out of it, taking about 5 to 7 minutes. I could drive her for 20 - 45 minutes with no problem till she acts up, or it could be no more than 10 minutes out. does this 2 to 3 times. just cuts off leaving me stranded on a one way street with no way for other cars to pass around me

First I thought it could be the pump had it checked out by my mechanic, she did the stumble while the was testing the pump pressure. He told me the pump was not the problem that it was ok. After 3 days in the shop the only thing he could tell me was that it was an intermitent problem with the throtle body... due that she is not sending any codes he siad it was hard to diagnose where it might exatly the problem is. I woul like to see if any of you has had this problem or what you think it might be. Where should I start to look and do first..

Took her to other mechanics and they won't touch her since she is not showing any codes. and i defenately don't want to go to the stealership... the'll ask for an arm and a leg,

 

[CaptainXL]

Cranking but not starting could be ignition switch or crankshaft position sensor if the fuel pump can be heard running when you first turn the key to run.

 

[McGMT]

What was the part number on those ACDelco plugs you put in it?

 

[limequat]

Maybe try a fresh PCM. Do you have a friend with a TB you can swap parts with?

 

[Wooluf1952]

Maybe try a fresh PCM. Do you have a friend with a TB you can swap parts with?

IIRC, you can't change PCM's without programming in the different VIN. I may be wrong.

 

[xhondastyle07x]

Did you disconnect the battery after doing the service to do pcm relearn? Double check the seating on the plug/coils to make sure they are making contact correctly.

 

[CaptainXL]

Did you disconnect the battery after doing the service to do pcm relearn? Double check the seating on the plug/coils to make sure they are making contact correctly.

Unplug a couple coils and see if it starts. Bet it will.

 

[BlackoutTBEroc]

I think You didn't unplug the battery for 30 min .. Or did you? Car has to react to the clean throttle body ..

 

[Harpo]

Unplug a couple coils and see if it starts. Bet it will.

Please don't try to start it with the coil/s disconnected, it would probably ruin the coil/s.

Don't ask how i know

Another car ,another life

 

[CaptainXL]

Please don't try to start it with the coil/s disconnected, it would probably ruin the coil/s.

Don't ask how i know

Another car ,another life

How do you ruin a coil if it's disconnected?

 

[Wooluf1952]

How do you ruin a coil if it's disconnected?

Disconnected from the spark plug, but still connected to the wire?

 

[CaptainXL]

Disconnected from the spark plug, but still connected to the wire?

I suppose if the coil is on the verge it might cause a problem. But i have seen mechanics just pull up the entire coil while still running to do a power balance test. They don't seem worried about it. I was just trying to make a point that a no start condition is unlikely caused by the coils.

 

[TBDriver]

capptainXL

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Cranking but not starting could be ignition switch or crankshaft position sensor if the fuel pump can be heard running when you first turn the key to run.


With this i can start, the mechanic told me that it as the throttle body but it cost an arm and a leg down here. The pump can be heard when you turn the key, after she dies she just sounds like she has a big miss fire, and if you step on the gas eather she dies back out or reves up to 1200rpm, sometimes comming out of this slump and getting back to normal

 

[TBDriver]

Did you disconnect the battery after doing the service to do pcm relearn? Double check the seating on the plug/coils to make sure they are making contact correctly.

the battery was disconnected for approx. 45 min till they cleaned the throttle body and worked on the coils chekingthem one at a time.

 

[TBDriver]

Thank you all for your input, let me know what else shout I be looking out for. Couse that throttle body cost $545 down here.

 

[CaptainXL]

People with throttle issues sometimes have pending codes. I would have it scanned.

 

[Harpo]

I suppose if the coil is on the verge it might cause a problem. But i have seen mechanics just pull up the entire coil while still running to do a power balance test. They don't seem worried about it. I was just trying to make a point that a no start condition is unlikely caused by the coils.

They should be worried!!

All newer coils, especially multiple coil systems are extremely sensitive if not connected to the spark plug.

 

[Ed H]

Just curious. If you are convinced it is the throttle body, can you purchase it online (~$200) and swap it out at home? Good luck. It's tough to troubleshoot without codes...

 

[CaptainXL]

They should be worried!!

All newer coils, especially multiple coil systems are extremely sensitive if not connected to the spark plug.

Wow. Ok I am not sure what I was drinking or smoking when I typed that but..your exactly right. Probably because I have been pulling coils off the engine alot lately I was just thinking about it. Just disconnect the electrical connector going to the coil instead. You don't want to get lit up.

 

[TBDriver]

People with throttle issues sometimes have pending codes. I would have it scanned.

No pending codes had it scanned by my mechanic twice.

 

[TBDriver]

Today She did the samething again but was not comming out of the slump, I opened the hood and just out of curiosity I Shook the throttle body cable harnes and the one that goes to the cam sensor. Went to start her up and she started with no problem. so I'm thinking I might have a bad connection somewhere, I'm going to have an electromechanick have a look at her, will keep you posted.

 

[CaptainXL]

Today She did the samething again but was not comming out of the slump, I opened the hood and just out of curiosity I Shook the throttle body cable harnes and the one that goes to the cam sensor. Went to start her up and she started with no problem. so I'm thinking I might have a bad connection somewhere, I'm going to have an electromechanick have a look at her, will keep you posted.

If it's not the wiring harness there are couple strong possibilities I can think of based upon past members issues here on the forums.

1 - If there is oil in the CPAS connector replace the CPAS and clean the connector.
2 - If the Camshaft Position Sensor is loose tighten the bolt.