97 Blazer - jerking going down the road

[97BlazerLT]

I have a annoying problem with my Blazer that no shop can pin point what it is. I will be traveling down the road at highway speeds (40 mph+) and it will jerk once in a while. It is not a steady jerk, it will happen once evry mile to once every 10 miles. No matter the weather conditions (heat,cold,rain, dry,Humid). No Warning lights on dash.
Was hooked up to a computer -- Only thing that it said was that it droped 500 RPM's. It is almost like i am not getting the coorect amount of fuel. If I turn the AC on it will die on me going down the road. the Fuel filter has been replaced. Fuel Pressure checked. Intake gaskets replaced. Replaced Plugs and wires. Injectors were cleaned. It is not the Transmission. That was replaced and checked. I have spent ALOT of $$$ on this already($2100+). I dont want to spend too much more on repaires that are not going to fix the problem. Is there anything else it could be???

[mike2004tct]

Originally Posted by 97BlazerLT

I have a annoying problem with my Blazer that no shop can pin point what it is. I will be traveling down the road at highway speeds (40 mph+) and it will jerk once in a while. It is not a steady jerk, it will happen once evry mile to once every 10 miles. No matter the weather conditions (heat,cold,rain, dry,Humid). No Warning lights on dash.
???

It could be a plugged EGR valve. I had the jerking motion happen at constant speed going down a level road. While accelerating, it didn't happen.

[97BlazerLT]

Originally Posted by mike2004tct

It could be a plugged EGR valve. I had the jerking motion happen at constant speed going down a level road. While accelerating, it didn't happen.

I will try to replace that- and see what happens with that... I will Post when it is done....

[Jeremy Fitch]

Originally Posted by 97BlazerLT

I will try to replace that- and see what happens with that... I will Post when it is done....

No need to replace.. just take it off clean it up and but on a new gasket.

[drdd]

sorry ... just had to laugh at the subject title of your post !1

Originally Posted by Jeremy Fitch

No need to replace.. just take it off clean it up and but on a new gasket.

[BlazerLT]

Do a tuneup.

[Jeremy Fitch]

Originally Posted by drdd

sorry ... just had to laugh at the subject title of your post !1

LOL, yes that could be dangerous!

[Rick1488]

LMAO

[97BlazerLT]

Originally Posted by Rick1488

LMAO

OK OK!! When i wrote it i was not even thinking anything like that --but it does sound funny!! Anyone else have any ideas??

I have did the Tune-up --- no help...

If it was the EGR Valve wouldn't the Servicce Engine Soon Light come on or Wouldnt the computer pick it up. Cause neither happened..... The computer said it dropped 500 RPMs and thats the only thing that it came up with....

Anyone else have any ideas??

[drdd]

have you cleaned the throttle body? the IAC?

clean that EGR ... its too easy not to ...

have you changed your fuel filter?

describe the AC conditions more ... does turning on the AC ALWAYS make the engine stall ? more details ...

Originally Posted by 97BlazerLT

OK OK!! When i wrote it i was not even thinking anything like that --but it does sound funny!! Anyone else have any ideas??

I have did the Tune-up --- no help...

If it was the EGR Valve wouldn't the Servicce Engine Soon Light come on or Wouldnt the computer pick it up. Cause neither happened..... The computer said it dropped 500 RPMs and thats the only thing that it came up with....

Anyone else have any ideas??

[97BlazerLT]

Originally Posted by drdd

have you cleaned the throttle body? the IAC?

clean that EGR ... its too easy not to ...

have you changed your fuel filter?

describe the AC conditions more ... does turning on the AC ALWAYS make the engine stall ? more details ...

Throttle Body has been cleaned. Fuel filter Has been changed. Plugs and wires Replaced, Thermostat replaced, Air Filter replaced, Whole fuel system cleaned. Coolant Flushed and Raidator Replaced, Intake gaskets and all gaskets.(Upper Engine was taken apart and Cleaned) Transmission was taken out and Rebuilt. All Fluids were changed. And everything was greased properly. Fuel Pressure has been checked and is good. My Blazer has been hooked to differant computers and guages and testers and Nothing..... No Service Engine Soon Lights or any other Idiot lights come on.


How do i clean the EGR??

Could it be PCV valve or O2 sensors have anything to do with it??

When AC is on my Blazer will Stall or loose Power to a point just before stalling 1000 RPMs when traveling 60. And will stall also. It seems to me and all the shops that i have taken it to figure That I am not getting enouph Fuel.

[drdd]

probably not o2 sensors ... they would give codes if faulty

change the PCV !!! a $3 , 1 minute chore ..

EGR - remove the 2 bolts that secure it to the intake ... soak it in throttle body cleaner and use a toothbrush to clean the carbon out - use a new gasket and re-install - EASY to do !! probably the most common cause of "hiccups" and "rough idle"

how is your belt tensioner ?

how old is the belt?

have you ever had your ignition switch replaced ?

cap and rotor ?

Originally Posted by 97BlazerLT

Throttle Body has been cleaned. Fuel filter Has been changed. Plugs and wires Replaced, Thermostat replaced, Air Filter replaced, Whole fuel system cleaned. Coolant Flushed and Raidator Replaced, Intake gaskets and all gaskets.(Upper Engine was taken apart and Cleaned) Transmission was taken out and Rebuilt. All Fluids were changed. And everything was greased properly. Fuel Pressure has been checked and is good. My Blazer has been hooked to differant computers and guages and testers and Nothing..... No Service Engine Soon Lights or any other Idiot lights come on.


How do i clean the EGR??

Could it be PCV valve or O2 sensors have anything to do with it??

When AC is on my Blazer will Stall or loose Power to a point just before stalling 1000 RPMs when traveling 60. And will stall also. It seems to me and all the shops that i have taken it to figure That I am not getting enouph Fuel.

[97BlazerLT]

Originally Posted by drdd

probably not o2 sensors ... they would give codes if faulty

change the PCV !!! a $3 , 1 minute chore ..

EGR - remove the 2 bolts that secure it to the intake ... soak it in throttle body cleaner and use a toothbrush to clean the carbon out - use a new gasket and re-install - EASY to do !! probably the most common cause of "hiccups" and "rough idle"

how is your belt tensioner ?

how old is the belt?

have you ever had your ignition switch replaced ?

cap and rotor ?

Belt 7 months old and is is tight as it is suppose to be.

Ignition swich was never replaced in the 1 year and 7 months that i have owned the Blazer. I Know it is a 97 and it is prone to have problems and it also has 140,000 miles on it. I am the 2nd owner. I Try to keep this in a Like new condition as possible. I clean the interior and exterior on a regular basis. and change the oil every 2,500 miles and keep on all regular routine maintance.

[drdd]

what was the fuel pressure? pressure w/ ign on and eng not running and then w/ eng running ..

Originally Posted by 97BlazerLT

Belt 7 months old and is is tight as it is suppose to be.

Ignition swich was never replaced in the 1 year and 7 months that i have owned the Blazer. I Know it is a 97 and it is prone to have problems and it also has 140,000 miles on it. I am the 2nd owner. I Try to keep this in a Like new condition as possible. I clean the interior and exterior on a regular basis. and change the oil every 2,500 miles and keep on all regular routine maintance.

[97BlazerLT]

Originally Posted by drdd

what was the fuel pressure? pressure w/ ign on and eng not running and then w/ eng running ..

I dont remember the numbers - but i was told by the shop that it is fine.