Hi, New here for a reason because I gave up with the Chevy Dealer service center. They can'tpin point the problem I having and just want to start popping in parts with no gurantee that it would even fix the problem.

Here's a short history of what happened. My blazer had really bad problems starting I had to spray starter fluid into the throttle body to get it started. Then it would run fine. Only had to do that when starting it. Eventually the engine would not start at all. So, I went to work on it.
I checked fuel pressure and it was really low. I replaced my Fuel Pump.This was my second fuel pump replaced within a one year period. Fuel Filter was replace at the same time.

I decided I might as well replace my Fuel pressure regulator because I already knew I had problems with the one I had. I could not maintain pressure after turning off the engine. The pressure would drop to zero really fast.

Spark plugs, Distributer rotor and cap, TPS sensor,ignition switch, battery, and alternator were also replaced recently.

The vehicle ran like a champ afterwards. Started on the first turn of the key. WooHoo!
But that didn't last long. After driving the vehicle for about 30 minutes on the highway I would start losing power. I'd be driving at 65 then all of a sudden my RPM's start falling, Engine speed is dropping by itself. I try give it more gas but that would make it worse. Eventually I could only get to about 10 mph speed. And if I floored the pedal it would almost stall out.
I pulled over to the side of the road and turned the engine off. Let it sit for about2 minutes and started it back up again. Now if was good again. I could get back up to 65 mph and drive normally again. It was doing this every day during the hot summer weather. As the temperature outside started dropping (Fall season) the problem went away. Things were good for a few weeks.

Now it's really cold outside and the problem came back again only really bad this time. I can start the car fine. It will run good for acouple minutes. I can get up to 55 mph then I start losing power again. Can't even get it to go up a small hill in the road. I pull over off the road and let it sit for a few minutes then restart it. I can drive for about another minute or two and start to lose power again. I was able to get it to a near by dealership they had it for a week already. I told them everything I replaced. They supected leaky fuel injectors. I asked them if they can test them and find out which one was leaky. They couldn't because they didn't want to spend the man hours taking them apart incase they were good. They wanted me to take the car back and test them myself. So, I was ready to just go and get the car and try and get it home. Already the have billed me $300 in labor for nothing. Well when I went to pick it up they wanted to keep it for another day because supected that maybe it wasn't bad fuel injectors and said it could be the VCM Module. I asked it were sure thats what the problem was. They said no not really and might not fix the problem at all. But they wanted to put one in at my cost anyways (another $500) no gurantee it would solve he problem. Well I told them no, and I'm going to pick up the car tomorrow.

So,now I'm out$300 and stillhave the loss of power problem. Thought maybe someone here might have some clue as to what might be causing this. The dealer saidthe car runs good until it gets warm then runs reallybad. I believe the said to was throwing a whole bunch of codes.
Also I did notice that when this power loss problem had gotten really bad my "Service Engine Soon" Light flashes.I've never seen it flash before. They (the dealership) said that was a sign of a really bad problem.

Sorry if I went overboard here with all this but thought it would give some idea of what went onwith this vehicle. Any advice or suggestions would ce

 

My first instinct is cat. Your cat is plugged up. The exhaust fumes back up into the engine and you lose power. Turn the engine off, or let it idle at low rps and it clears out enough for you to drive a little further.

My second instinct is ICM- first sign it is going bad is lose of power, engine dies, goofy timing, when hot. Once cool it returns to normal, until it gets hot again and the cycle repeats.

Beat on the cat with your fist, if it rattles, replace it.

Take the ICM to your local Autoparts store and have them test it. Make sure they do the test like 6 times in a row. You want it to get hot.

Anotehr test for a plugged cat is to disconnect your battery for 20 minutes. If you cannto start the trcuk again your cat is plugged. The puter monitors engine peramiters, it makes adjustments to keep it running properly. When you disconnect the battery the puter loose memory of what it learned, and it goes back to defualt mode. If it dont start, its becuase defualt mode is so far out of whack from what it learned.

These are strictly shade tree mechancis at its best.

 

Thanks, will give thesea look at when I get the car back from the Dealer tomorrow. Will report back on my findings. It's going to be a long trip back home with it as I'll have to pull over and turn of the engine and restart about every minute or two for about 10 miles.

Brian

 

Just got it back from the dealer. They must have cleared the codes on it because I didn't get a Engine Check light on. But I drove it for about 5 miles (it ran good) then the Check Engine light came on and was flashing. I started again to lose RPMs again, I slowed down and the flashing stopped then it was just a steady on light (not flashing). If I tried to accellerate faster, I couldn't gain up more speed. If I let up on the throttle just a little then my RPM's would go up slightly. I got it up to my driveway to my house but couldn't get it to go up it. I live on a little hill and the driveway is inclined up. I turned off the engine for about 2 minutes then started it back up. Then I had more power to get it up the driveway. It's now in the garage.
I have the receipt from the dealer. What a suprise. They decided not to charge me anything for the week they spent looking at it. Good decision by them I guess because they couldn't find what is causing the problem.
I had them copy the codes onto the receipt. So, here they are.
P0442 Evap System small Leak, (gas cap)?
PO122 TPS Low input voltage ( was replace with a new one by me)
PO131 O2 sensor circuit low voltage (Bank1/Sensor1)
PO300 Random / Multiple cylinder misfires (Reason for Flashing Check Light?)
PO137 O2 sensor circuit low voltage (Bank1/Sensor2)
PO141 O2 Sensor heater circuit malfunction (Bank1/sensor2)
PO143 O2 Sensor Circuit Low voltage (Bank1/Sensor3)
PO151 O2 Sensor Circuit low voltage (Bank2/ sensor1)

Can't see how all my O2 sensors could have went bad at the same time. Maybe I have bad connections to them? Or, maybe because the car was backfiring when this problem first started. Only did it a few times when I tried to give it more throttle.

Still, car warms up then throws these codes.

They (dealer) supectedVCM module.

Banged on the CAT and didn't here anything rattle. It's pretty tight and maybe I'm just not hitting it hard enough to move it. Keep thinking the ICM too. I removed it and cleaned the surfaces and replied alot of heatsink grease to it. It didn't have much on it and was abit dried up. I don't think I'll take it for a ride just yet. I did notice that on my way home I got the flashing Check Engine light then it went solid after reducing speed. Started out with no light, Dealer cleared codes I think. I believe it was doing the misfire on cylinders firstthen the other codes (TPS/O2 sensors)must have followed. I'm an electronic technician so I'm pretty good at trouble shooting electrical stuff. I know of a test I would do when I suspected a electrical component breaking down due to heat. I would spray the component with a can of freeze spray and if it then functioned normally it would be the bad part. Thinking of doing the same with the ICM and see what happens after it heats up and the car starts missing or misfiring.
Thing is I'm all out of freeze spray at the moment. But I have a can at work. It's 30 miles away though and don't think I'll try and drive there tonight.


Thanks,
Brian

 

Sounds like the cat is ok then. At least ift passed the beat test anyway.

P0300 eh?
Maybe try a test, how long can you drive it at a slower speed?

 

Well today bringing it home I drove about 8 miles going about 50 to 55 for about 6 of those miles. It started acting up and I reduced speed to about 30 for the rest of the trip and made it home till I got to my driveway. Then turned it off for about 2 minutes to allow to cool down. Then got up the driveway. It is a problem when the engine gets to it's normal operating temperature I guess. Then it loses power, sputters, misfires, etc...

Ran it in my driveway just alittle while ago and got it hot. It was putting much out smoke out of the exhaust. Maybe just water vapor I don't know. Maybe just a lot of water buildup in the exhaust system from condensation I think. Hope it's not coolent. Didn't normally do this alot. Only sometimes. Really cold outside today. Maybe about 20 degrees now. I'm in Buffalo, NY area.

Brian

 

This definitely looks like there is either a wiring or a PCM failure... Check over all of your grounds first and foremost.

If you have a pick-n-pull type yard close by, you may want to get a replacement PCM from there and see if that helps.

 

Looked at alot of sensor connections today and didn't see anything abnormal. Cleaned them anyways. Pulled off EGR valve to check if it was stuck butwas able to push on the little plunger and it is good mechanically.

By PCM do you mean VCM?Or, is PCM something different. This gets confusing as VCM can be called ECM too I guess.Again the Dealer suspected a faulty VCM but didn't offer any gurantee that replacing it would fix theproblem so I said no thanks. Can't afford trial and error troubleshooting. Even though process of eliminationmight help but would be costly.

This problem manifested I think after I changed the fuel pump, Fuel Filter,and the fuel pressure regulator.
I also had put in a new alternator, battery, distributer cap & Rotor, and Spark plugs just before I did the Fuel pump and pressure regulator. Before doing all that I didn't have this kind of problem. Well at least before my Fuel pump failed.

I keep thinking maybe it was something I did during all that work that I maybe overlooked. Like forgetting to reconnect something. I looked and looked but can't see anything I could have missed. Just appears to me like something is warming up then failing when the engine gets hot.
The only thing I replaced now was the TPS sensor because it came up in the codes. But I think the reason for the TPS code was because I was trying to accelerate and the engine wasn't responding the correct way and thinks the TPS was failing.

Gotta be a Nasa Rocket scientist these days with cars.

Well have to use my wife's car tomorrow and leave mine home to rot in the garage while I'm at work.

Thinking of getting a Code scanner but maybe someone can talk me out of it. Maybe something I can use to monitor things while I drive the car until it gets hot and starts to fail again. Would be nice to get somekind of report of what the sensors are doing.

Brian

 

The puter stores all teh parameters when a code is tripped. Go to Autozone and get them to read the codes, then ask them to read the freze frame data (not sure of the proper term). Its the information the puter stores when the code is tripped. While your at Autozone get them to test your ICM. When hot it dont want to play nice, when cool it will work great. It controls your ignition timing. Early sign of falure is acting up while hot and going back to normal when cool.

 

OK, I fixed my misfire problem. Had several misfires cylinder 1,2 and random. Turned out to be the new set of 6 Bosch Platium sparkplugs. Replaced them with ACDelco plugs and haven't had a misfire code in a few days. But I still have a loss of power problem and getting a new code on the scanner I bought. It's P0153.
After reaching operating temperature it bucks, backfires (sounds like coming from the throttle body) front of engine. If I floor the gas the RPMs jump all over the place (goes up & down) and I hear backfire sounds.
So far I replace the TPS, IAC, New Plugs, New Plug Wires, Fuel Pump a few months ago, fuel filter, Fuel pressure regulator.

Could the O2 sensor (slow response) cause this probem? Can't get this vehicle inspected until I can get this thing from throwing codes. It'salmost 30 days past inspection (overdue). In about a week I'll be getting a Notice from NY DMV that theyarecanceling my registration because it not inspected. Really need some advice here. Wouldbe greatly appreciated.

Thanks,
Bryan

I can post freeze frame data if that would help for the code. I also collected live data when the car was bucking,backfiring,etc...
Basically I floored the gas and triggered the coderscanner to grab the data. So, it verry erratic.