2000 Chevy Blazer Acts like it wants to cut out at 70+mph o

Tiny
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  • 2000 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 162,000 MILES
I have a 2000 Blazer with 162000 miles. Three years ago I replaced the fuel pump. That lasted two years. I bought another guaranteed for life fuel pump on EBay. Right after I put it in the Blazer would start fine but turning a corner it would act like it wanted to stall. If you went into passing gear it would rev but not go any faster. Then I got the check engine light. I had a scan run and it said two things. Fuel pump not delivering enough fuel and O2 sensor port 1. So I replaced the sensor. Same problem. Then it started to take three to four times to start. So I bought a new Delphi fuel pump made for my Blazer. When I took the old pump out I found that wires had come apart and parts were in the fuel tank. So I had the tank cleaned out. I put the new Delphi in. Starts the first time. I no longer have the problem of it wanting to cut out while turning.

Here is the problem I am having. I can drive at 65 fine, hit 70-75 and it wants to start cutting out. If I go into passing gear it starts to cut out but, it does gain speed. Then it will still act like it wants to cut out even when I slow down. And it idles fine after but when I start to take off it acts like it wants to cut out and die. If I let it cool off for a few hours I can drive it all over town with no problem unless I climb a hill and it goes into the passing gear. Then I have the same problem. On level ground I can drive for hours 65 and under.

So I took it to a mechanic who did a pressure check and scan. He said the pump is fine along with the pressure at and a little above 66 and no pressure loss even when turned off, no leaks. And it isn’t throwing any codes now. My check engine light is off. So he said do a tune up and we would go from there. He charged me $35.00 for the pressure check and to run a scan. He wanted to do the tune up for a few hundred. That I can do. Anything they do around here is expensive. He named off some things it may be and what he would have to do to repair or even check. He gave prices none of which were under $300.00 some exceeding $500.00. He told me I could safely guess that it will cost me around $800.00 minimum and maybe more. So, I changed the plugs, wires, PCV, fuel filter, oil change, air filter, cap and rotor, new thermostat and did a flush. The temp is fine on it and it is not overheating. I was just trying to make sure that wasn’t it. But it is still doing the same thing, only in the ranges I mentioned above. I hope you have some ideas.
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Wednesday, August 25th, 2010 AT 12:03 AM

9 Replies

Tiny
DOCFIXIT
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Hi
Check voltage to pump engine running is it equal to voltage across battery terminals? If lower run an alternate ground off Terminal C Black wire. When Tech scanned what where names of parts he suggested to change?
Let me know
Thanks for donate
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Wednesday, August 25th, 2010 AT 12:43 PM
Tiny
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Thanks for the reply.

He informed me that it could be the fuel injectors or a fuel regulator and maybe a spider something that goes to the fuel injectors. To which he would have to keep it a few days and slide a scope down to look at them. He was not talking a dyno. He was talking about a scope like a doctor uses to look inside the body because he showed it to me. He said if the injectors or that spider are cracked or leaking it may be a flooding type problem. If any of those are the problem the palinum would have to be taken off which will cost a lot in time and the parts he said are not cheap. That to me did not sound right if during the pressure test after starting and running it then turned off it did not drop in pressure. But what do I know? Then he said it could be a clogged or pinched fuel line which would have to be replaced which again will not be cheap. Or it could be the computer going out. Or a coil or a sensor and he just kept naming things. He said without it throwing a code it could be a million things. He said if it were throwing a problem code then he code be a lot more specific. Like I said the check engine light is not on. Like trouble shooting trial and error. I think the sensors, MAF and the EGR valve were the cheapest he named off which would run about $300.00+ for him to figure out and replace. I did clean the MAF carefully with MAF cleaner during the tune up. The thin wire/s are still intact and it appear ok. I forgot to mention that. He also said it could be the catalytic converter.

I also called the dealership here just to inquire and they are totally out there. They wanted triple what he wanted.

After installing the new pump I noticed that the Alt gauge is running one notch lower when all this happens. But when it is cool and not pushed it is at 14. I just thought the pump was more powerful and pulling more. I don't know if that means anything to you. Today I stopped at Autozone because they will scan for free. They scanned it with no errors. And no pending errors. They told me it may have to happen a few times for the computer to produce a code.

I'm going to try what you suggested over the weekend. Because I will have to borrow a voltage meter. Mine is at my ex wifes house.
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Wednesday, August 25th, 2010 AT 10:43 PM
Tiny
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Allthough spider is common problem you are right it would have not held pressure when engine was shut off.
The ground problem is VERY common on GM cras and trucks they won't admit it. Kind of a known fix. Maybe what is going on with Blazer. Cleaning MAF and throttle body good to do
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Thursday, August 26th, 2010 AT 11:29 AM
Tiny
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I tweaked my back the weekend before last. Anyway it was a long weekend this past weekend. So I bought a scanner and a new digital multimeter. I checked the battery while running and it was at 14. Then I checked the fuel pump while running and it was lower. I tried to wiggle the wires while I was under there just to see if there was a change. But there wasn't. So I added the other ground as you suggested. I did get a chance to go down the large hill and back up with it dropping into a lower gear. It did not choke at all. So that is a good sign. Tomorrow will be the real test when I have to go to the other town to pick up my son. Then I can get it up to 75 etc. I will let you know the outcome.

Thank you again,
Don
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Wednesday, September 8th, 2010 AT 11:16 AM
Tiny
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Good news let me know what happens
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Wednesday, September 8th, 2010 AT 3:12 PM
Tiny
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Well that wasn't it. I had no problem getting up to 75 at a steady increase without it dropping to a lower gear. Then I got in some traffic which slowed me down to 65. As soon as that cleared I stepped on it to get back up to 75. It dropped into passing gear. The RPM's went up and the speed was going up but very slow. Then it started the same thing. Choking and sputtering. Three hours later after we were home we decided to go out to eat. Even at low speeds it would start to sputter and you had to push down a little more on the gas to get it to speed up. Then it would be fine until you came to a stop. After the stop same thing. This morning it is still doing it but not as bad. And it still isn't throwing any codes. Any other ideas?

Thanks,

Don
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Friday, September 10th, 2010 AT 1:12 PM
Tiny
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Well that wasn't it. I had no problem getting up to 75 at a steady increase without it dropping to a lower gear. Then I got in some traffic which slowed me down to 65. As soon as that cleared I stepped on it to get back up to 75. It dropped into passing gear. The RPM's went up and the speed was going up but very slow. Then it started the same thing. Choking and sputtering. Three hours later after we were home we decided to go out to eat. Even at low speeds it would start to sputter and you had to push down a little more on the gas to get it to speed up. Then it would be fine until you came to a stop. After the stop same thing. This morning it is still doing it but not as bad. And it still isn't throwing any codes. Any other ideas?

Thanks,

Don[/quote:985f353e67]

I spoke to soon this morning. Because all I did was drive it around two blocks. My son and I went to get groceries. It acted sluggish from the second we pulled onto the road. The max speed limit is 45 in town and it started to really act up bad. The engine sound got a low rumble and it was cutting out bad and when it would catch I would hear a bang like metel under the vehicle. It was also changing gear erratically. The store is about a mile and a half from here. We made it to the store. We needed groceries anyway even if I would have to call a tow truck. Some kid in the lot walked up and asked about it. I told him what all had happened. He said it could be a coil or the computer going out. I took it with a grain of salt because he looked really young. Anyway we were in the store an hour. When we got ready to leave it worked fine. Very strange. And still the service engine soon light Did Not came on. And it is still not throwing a code.
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Friday, September 10th, 2010 AT 6:12 PM
Tiny
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Well that wasn't it. I had no problem getting up to 75 at a steady increase without it dropping to a lower gear. Then I got in some traffic which slowed me down to 65. As soon as that cleared I stepped on it to get back up to 75. It dropped into passing gear. The RPM's went up and the speed was going up but very slow. Then it started the same thing. Choking and sputtering. Three hours later after we were home we decided to go out to eat. Even at low speeds it would start to sputter and you had to push down a little more on the gas to get it to speed up. Then it would be fine until you came to a stop. After the stop same thing. This morning it is still doing it but not as bad. And it still isn't throwing any codes. Any other ideas?

Thanks,

Don[/quote:6428a4fceb]

I spoke to soon this morning. Because all I did was drive it around two blocks. My son and I went to get groceries. It acted sluggish from the second we pulled onto the road. The max speed limit is 45 in town and it started to really act up bad. The engine sound got a low rumble and it was cutting out bad and when it would catch I would hear a bang like metel under the vehicle. It was also changing gear erratically. The store is about a mile and a half from here. We made it to the store. We needed groceries anyway even if I would have to call a tow truck. Some kid in the lot walked up and asked about it. I told him what all had happened. He said it could be a coil or the computer going out. I took it with a grain of salt because he looked really young. Anyway we were in the store an hour. When we got ready to leave it worked fine. Very strange. And still the service engine soon light Did Not came on. And it is still not throwing a code.[/Quote:6428a4fceb]

Hello again, finally maybe,
Well I may have discovered the other half of the problem. And this may help some readers as well because I couldn't believe it myself. I started thinking back on when I did the tune up. I did that the day before installing the new fuel pump. I decided to recheck my work. So I pulled the plugs (which is a pain) etc. When I got to the rotor and cap is where I found a problem. I pulled the cap off. I noticed the rotor looked badly worn, pitted deep in the center and pitted on the outer metal and heavily tarnished. It looked like a used rotor. But you could tell by the plastic that is was new. When I went to remove it I found it wasn't tight at all. It was basically floating freely. I tried to tighten it down to no avail. One side would tighten to a point and a little more it would come free. So I took it all the way off and noticed that the screws were not the same size. They were both the new screws that came with it because the blue was still on them. You cannot tighten down on plastic a lot for fear you would break it. I noticed one of the screws was a little thinner with different threading. I mean you have to look really close. I also noticed the plastic pin on that side that fits into the guide hole was broken off. I had a friend run me up to the parts store and I showed it to them. They pulled another one and guess what? The same thing. Lucky I had kept the original screws and the thicker one was what is suppose to be in it. The man even looked it up on the computer and sure enough the thicker one was the correct one for both sides. So he started looking at the case of them. All were the same. Then he pulled another case and it contained both the correct screws. He said that it sometimes happens. Anyway he switched them out for me. He also informed me that a lot of people had been coming in with the same problem I had. It had baffled all of the employees and they had been selling coils trying to help people trouble shoot the problem. It seems that this rotor fits a few other vehicles besides the 2000 Blazer.
I'm no tech by any means. But I can see how a gradual increase in speed might work alright like mine did. But once you kicked into passing gear at a high speed that rotor must have been just hitting where it could. Throwing the spark off and confusing the computer etc. I installed the new one with the correct screws and like I said the max speed here in town is 45. I punched it a lot. I could instantly tell it was better. The big test will be when I have to pick up my son Thursday and hit the expressway. I do think the extra ground helped and was a major factor as well. I'll let you know. But if you want the name of the parts store email me private. Because they have been really good to me and it isn't their fault they got a bad case of rotors. But everyone needs to look at the new screws and the old ones. It's something anyone could miss. Especially if they are not a mechanic. I think even a mechanic could make this error.

So far I want to thank you for all your help. It's a major thing for me to work on my car. I'm a 100% disabled vet. They retired me a few years ago. That's why I look to you guys for automotive answers. You guys have always steered me right. Pat on the back!
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Sunday, September 12th, 2010 AT 7:45 PM
Tiny
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Good to hear you solved problem and a weird one for sure. Between China and Mexico it is a wonder any of are stuff runs
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Tuesday, September 14th, 2010 AT 3:03 PM

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