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 noadjustments in pressurewhile 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 veryslowly accelerates .

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.

 

How many miles are on this Blazer? What is the service history?

 

mine did the same thing kinda so my mac.changed my ox sencer

 

Well I'm with Kordog..what's the service history. I'll assume you have not done anything, adjust accordingly..
[ul][*]Clean MAS sensor in air intake[*]Check for vacuum leaks[*]Clean throttle body (not your problem, but might as well)[*]Double check the connector to the temp sensor[*]Replace spark plug wires[*]Replace cap & rotor[*]Replace Spark Plugs[*]Replace plugs, gaped correctly[*]Replace MAP sensor[*]Replace TPS sensor[/ul]
I'm sure there are a couple other ideas that the experts will recommend you check or replace.

What is your gas mileage. Has it gone down the tubes with your problem?

 

The vehicle only has 46,000 miles. It was orignally from California.

As far as service goes, just oil and regular maintence. Nothing substantial ever needed.

Gas milage hasnt really been any worse but i cant give you an accuarte answer becuase it hasnt been drivin very much since this has began.

So your thinking regular maintence issues?

 

Does anyone think it could be a bad Mass Air Flow Sensor?

 

I only ask that becuase i unpluggted the mass air flow sensor and the car doesnt jerk, it has absolutely no power, but it doesnt have the jerking problem.

 

Check to see if the MAF is dirty, sometimes excessive dirt/oil can cause a "surging" problem. If there is a K&N oiled foam filter there is a problem with excess oil from the filter getting onto the wires of the sensor and messing up the readings it needs. Get either someCRC Electronic MAF Sensor Cleaner or Radio Shack Contact Cleaner. These should work to clean off the MAF.

To clean it just pull it out from the air intake hose and airbox lid by loosening the clamps that hold it in place. Loosen/remove the 4 socket head screws that hold the two metal pieces together. Remove the plastic Sensor piece and the spray liberally with cleaner, both front and back sides making sure not to damage the wires (MAF sensors are delicate and expensive). If dirt build up is so heavy a very light cleaning with a cleaner soaked cotton swab (Q-Tip) maybe needed...Then when you are done re-assemble the sensor pieces and put back into airintake hose and airbox lid...

 

well its not the Mass Air Flow Sensor, just replaced it and it didnt fix anything.....same issue...

Im being told it could possibly be the fuel injector spider?

Any thoughts?

Thanks for the help guys....im going crazy.

 

Do you smell gasoline when you remove the air filter adapter on top of the TB???? If so then it is possible, if not then the problem is else where...Could be TPS out of adjustment or the IAC or a bad wiring to the MAF, IAT, TPS, IAC or the Computer itself....or a bad Camshaft Position sensor in the Distributor. Could be many things are you setting codes in the computer, have it scanned to find out this could lead you in the direction as to what area of the system is out...

Check the EGR valve on the front of the intake to see if carbon is keeping the pintle open....since this is happening after 5 mins or more then it has to be in the closed loop operation of the vehicle does it do it when completely cold????