Yeah, I used the heat sink grease on the Ignition Module. Should not really matter about the ambiant temprature though, as once the engine has ran for a half hour or so the under hood components are all going to get hot. This makes me question if it is an underhood component.

I have not had a chance to check it out this weekend as I was out of town.

 

Hi i have an'01 blazer 2dr 4wd. I have a similar problem but it isn't exactly the same It started almost a year ago one morning it wouldn't start I kept trying for about 20min finally it started(it was warm and dry out). Drove down the road about 10mi it started sputtering and the check engine light came on. Igot to where i was going sputtering the whole way turned the truck off. later went to leave wouldn't start for like20min got it started took ittoa mechanic. 3monthes and $1100he replaced my fuel pump ign module and a few other parts.I didn'thave a problem for a month. Then it didn't want to startsat for 10min trying to start got it started it drove fine. I have lived with this for almost a year it would do thiis about once a month I couldalways get it started eventually. Which brings me toitsrecent incedent I was driving down the freewaythe other day when it started sputtering it did this for a few miles then it died left me sittng 20 min before i started,drove a few miles and died again. I managedto make it almosthome like this (took a whilethough)until the battery died. got towed home.Let it sit for a hourcharging then it fired right up and ran fine I let it run for an hour no problem.the next morningstarted up just fine its ran fine since.If anyone has any adviceI ask you Please Help me Thank you

 

Welcome to the site.

Battery connections. Take your cables off the battery and make sure your battery posts are good and no corrosion. Verify your cables are not green under the protective sheath. Replace them if you suspect them or see any cracking.

Does your security light come on when it doesnt want to start? If so, it could be your ignition switch. Its under the dash, not where teh key goes. Mine went bad, and it wouldn't let me start the truck until it recognised the key, then it would run all day long. Mine was under warranty and the dealer replaced it.

third thought is ICM, if it was replaced, is there grease betweeen it and the heat sink (mounting brakcet). ICM will fail when hot, cools off and it works just fine.

Of the three, I suspect your battery cables first. they will be intermittent, and not really tied to cold or hot engine, not really tied to anything. Thet just act up. Bounce a few more times andd it may go away or get worse and die instantly.

 

Its probably not battery cables the truck doesnt lose all power. i think the ignition switch was replaced at the mechanics. I did replace the ICM, Im not sure about the grease.

 

After several weeks of running good...It came back!

This is almost as bad as a slasher film. The nightmare on Vortec Street.

This time I checked all of my grounds (they were tight) and replaced the O2 sensors. The computer did not show any screwy readings from the O2s but I took them out and shook them; they rattled like the ceramic elements were breaking up.

If this does not fix them, at least I have a head start on the 100k maintenance.

 

O2s shouldn't sounds loose or like things are rattling around inside... But I would think that something would trigger a light if they were breaking down inside though...

Hope this gets it...

 

Yeah, the rattle kind of concered me.

So far it has not fixed the problem, but it has made a great improvement. It still feels like there is a hole in the powerband around 2000 rpm and will surge; however it is still an off and on arrangement. I will say that when it does act up, it is not nearly as severe as it was before the O2 replacement.

I dumped in one of the big bottles of Techron, maybe I have a sticky injector. It is worth a try and much cheaper than replacing parts.

Just out of curiosity, I disconnected the hard plastic EVAP line from the valve on the intake and capped off the solenoid valve. No improvement, but I can eliminate the whole EVAP system now.

 

What are you hoping to gain by removing the EVAP system, other than a CEL (check engine light) that is???

 

I did not remove the EVAP system, I temporarily blocked off the vacuum line to see if the EVAP system was causing a vacuum leak. There was no improvement, so I was able to rule out the EVAP system as a possible source of my problems. I am also confident that the vacuum solenoid is not bad/leaking.

 

Ah I see.