2001 Tahoe Blinking Check Engine Light?

[Justin509]

2001 Tahoe
205k
5.3
4wd

I just had a trip to Oregon about 1k miles round trip. Just as I got back in town I had my cruise control on and was doing about 65mph and started to go up a hill and I noticed when it went from 1500rpm to 3000pm it was pulsing like it wanted to go faster but it wouldn't like a miss fire. Then I noticed the check engine light blinking. So I turned cruise control off and brought it down to 65mph and about 1800rpm and the blinking check engine light went off.. Then I wot to see if it went away and it did the same thing. Check engine light started blinking... I found a little info saying that when the check engine light blinks that means its a miss fire. So I took it to auto zone and had no codes.. So I then pulled the maf and cleaned it. Still no change..So then I pulled the plugs which look original and changed them along with new wires. Still no change! So whats my next step? Coil packs?? Is their a way to test them? Anyone have this problem?

 

[Thumper8302]

as far as the coil pack testing goes u can take them up to autozone and they will check them for free.... kinda funny how no codes were stored in memory. kinda makes me wonder if ur tranny is starting to have issues.. hope u find the problem man

 

[fire730]

Usually a flashing CEL means that catalytic converter damage is likely to occur. Usually a misfire causing raw fuel to be dumped into the converter. As far as pinpointing which one it is hard to find out which one until the computer tells you which cylinder is causing it.

 

[sumo]

Usually a flashing CEL means that catalytic converter damage is likely to occur. Usually a misfire causing raw fuel to be dumped into the converter. As far as pinpointing which one it is hard to find out which one until the computer tells you which cylinder is causing it.

exactly. But its not Likely, its Means it is.

 

[SunlitComet]

A flashing CEL is a active misfire and a scanner with enhanced gm diagnostics can tell you the misfire history of each cylinder to pinpoint which cylinder(s) is given you the problems. Look for stored codes as well not just active one. It should be address ASAP as it could not be just a malfunctioning injector that is putting out no fuel but also could be a no spark issue where raw fuel gets dumped into the converter causing it to overheat and melt the substrate but also washing down the cylinder wall.

---------- Post added at 09:55 PM ---------- Previous post was at 09:54 PM ----------

BTW Justin,

 

[Justin509]

So for the last day I have been trying to figure out what the problem is. I pulled the tb off and cleaned it. It looks like it has never been touched! But still no help. Also is their a way to test the maf sensor? I'm also thinking that it could be and injector but I am not sure which one since I have no codes. I'm picking up a scanner today and will see if any have been stored. I'm hoping that one is in their and will tell me whats going on.
Before

After

---------- Post added at 10:20 AM ---------- Previous post was at 10:15 AM ----------

Also here is a shot of the old plugs.

 

[fire730]

Usually the MAF will set a code.

You can eat off your TB now. But a dirty TB wouldn't cause a stumble anywhere over idle speed.

Those plugs were definitely wiped out.

What did you replace them with?

 

[SunlitComet]

1. yeah that is 205k miles on that tb.
2. Those plugs are beyond gone. Are they not supposed to be platinum type?
3. the scanner will either read back the output voltage or Air poundage that the Maf sees.

 

[fire730]

I thought that all the 5.3s used platinum plugs. He definitely wore off the platinum on those babies.

 

[SunlitComet]

those do not look like platinum's at all. The look to straight solid core to me.

 

[fire730]

If I remember correctly the Delco plugs have a spot of platinum on the ground electrode that you can see as the little white dot on the plug on the bottom.

 

[SunlitComet]

there iridium for 2001 look like this:

---------- Post added at 09:07 PM ---------- Previous post was at 09:06 PM ----------

BTW, why is there a hole in the throttle plate?

 

[fire730]

They are worn out but I really can't see those being original plugs. 200k miles. I just cant see that happening. Not impossible but I cant see it happening.

 

[SunlitComet]

I think someone just replaced them with the wrong ones.

 

[Thumper8302]

damn.. that throttle body was nasty as hell... im pushin 240xxx on mine and ive only cleaned mine with a tooth brush and a rag with it still on the motor.... kinda been leery on yankin it and actually CLEANIN it... was it a pain gettin the butterfly out? and how much of a pain was it installin it back to the manifold?

 

[Justin509]

I put autolite xp iridium plugs back in. As far as the plugs being factory that's what it's looking like. They are acdelco ngk pztr5a and are long gone! Lol... As far as cleaning the tb while it was still bolted up I didnt want dirt and gunk travel down stream to my injectors. After I cleaned that I pulled both fuel rails and made a little home made injector cleaning setup. And I'm on my last injector... Ill put it all back together and see how it runs. If it still running bad then I guess it's gonna be one of the coils.

 

[Justin509]

This is the home made setup I made to clean the injectors.. Dont laugh lol it works..

---------- Post added at 10:28 PM ---------- Previous post was at 10:24 PM ----------

O and after all the injectors were cleaned and put back in it still is missing! so I will be getting it on a scanner in the morning to see what is exactly going on.

 

[Diggerdan11]

The same exact thing just happend to me this last weekend. The week before the CEL came on on the Tahoe so I went to o'reilly's and borroed there Scanner and it showed the P0420 and P0430 codes which are Catalyst efficency belwo threshold. I figured it would not be that big of a deal to drive it for a couple weeks till i could get it figured out. Well i attempted to accelerate up a hill and the truck lost power the RPMs started to bounce and the CEL started flashing. I took it right back to O'reilly's and it showed a code saying there was a missfire. I have read that a clogged Cat could definetly cause a problem within the Cylinders and a missfire because the gas has not where to escape.

Its strange that the scanner did not show a code. I went to Autozone to use there scanner and it would not connect to my tahoe for some reason. you may want to go to another auto place and seem if they have a better scanner


BTW what part of Oregon did you go to?

 

[SunlitComet]

The same exact thing just happend to me this last weekend. The week before the CEL came on on the Tahoe so I went to o'reilly's and borroed there Scanner and it showed the P0420 and P0430 codes which are Catalyst efficency belwo threshold. I figured it would not be that big of a deal to drive it for a couple weeks till i could get it figured out. Well i attempted to accelerate up a hill and the truck lost power the RPMs started to bounce and the CEL started flashing. I took it right back to O'reilly's and it showed a code saying there was a missfire. I have read that a clogged Cat could definetly cause a problem within the Cylinders and a missfire because the gas has not where to escape.

Diggerdan you definitely need new converters.

 

[Diggerdan11]

Diggerdan you definitely need new converters.

yeah i know, bad.

Im going to get them in a few more weeks. Im getting maried in a couple weeks so im going to try to wait until after that to do it, since im going to replace them myself. For now my Fiance is only allowed to drive it to and from work which is about a mile and a half each way.