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2001 Blazer, Weird Surging under a load? Ideas?

kylekkylek Posts: 1
edited March 2014 in Chevrolet
I have a 2001 Chevy Blazer.

Im having a very weird surging issue when i drive the truck which is so bad its really undrivable right now. Ive checked the fuel pressure while im driving and its reading accuratly, right around 60 under a load with no adjustments in pressure while the surging is going on. Just think of being in the truck and you would floor it then let off floor it and let off, thats what it feels like. Ive takin to a couple places and noone can figure it out.

At idle truck sounds normal. It begins after about 5 min or so of driving and doesnt stop, and vehicle very slowly excelerates.

For awhile it was throwing PO128- Coolant Temp Sensor. I replaced this part and it still does has the problem.

So now, same prob, but no service engine light after i reset it with the obd 2 reader. I was told there that it could be a bad Fuel Injector Module, but i dont even think that the vehicle has one.

Any ideas what to check would be greatly appreciated.


  • repairdogrepairdog Posts: 948
    If the fuel pressure is good and a new fuel filter installed then would point to electrical/sensor which there are a bunch. Yes, you have injection under the upper intake manifold - a spider assembly that fires each individual poppet and a pressure regulator. Look for vac line leaks, then change the cap/rotor first to rule out. Then its a sensor search so if you are not really into electrical stuff take it to a GM dealer for a scan and they should be able to pinpoint in about an hour or approx $90. Money well spent.
  • can you tell me the location of the sensor we have the same problem and need to replace it [email protected]
  • repairdogrepairdog Posts: 948
    Same as other post between rear 2 plugs drivers side. Usually an under temp is caused by a thermostat stuck open and remember to flush/change that Dex cool every 3/36 - that GM BS on 5/100 will trash the cooling system and gey a 50/50 mix in the system filling the res to the hot line when cold - have to keep air out of the Dex cool systems.
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