s-10 blazer help

[red2004 TRX450R]

Pulsating RPM’s HELP

I know some one that has a late model 4.3 blazer. And a lot of times when you are just going down the road the RPM’s with start dropping down and up like a 1000 RPM’S.

EX going along at like 3000 then drop to like 2000 then back to 3000 and so on……… like every ½ second.
It will do it for a wile and them it will stop and then it will come back.

She took it a small shop and they sead it was in the evack (sp) system and there were too many things to start replacing.


HELP

[300exOH]

Sounds like the problem I had on my Blazer. The EGR valve clogged up with carbon. My buddy who is a mechanic took it off and used a pin and carb and choke cleaner to clean out the valve and bolted it back on and it fixed it. Not sure if this is your problem but it's worth checking into. I guess it's common on 4.3's.

[Heybo]

Does the engine miss or cut-out? Is the check engine or service engine soon light on? Did the shop she take it to check and see if there were any codes in the computer?

[red2004 TRX450R]

Does the engine miss or cut-out? Is the check engine or service engine soon light on? Did the shop she take it to check and see if there were any codes in the computer?


it dont realy miss or cut out. it feels like it is dropping a cuple hunderd rpms and then regaining them!
ya the check engine light comes on and off and the little shop said it was the evack (sp) but witch part they don't know!!!

I first thought that the converter was locking up and not un locking but u can shift it and the proplem remains

[Heybo]

Did the shop tell you what code was in the computer?

[chucked]

Originally posted by red2004 TRX450R
Pulsating RPM’s HELP

I know some one that has a late model 4.3 blazer. And a lot of times when you are just going down the road the RPM’s with start dropping down and up like a 1000 RPM’S.

EX going along at like 3000 then drop to like 2000 then back to 3000 and so on……… like every ½ second.
It will do it for a wile and them it will stop and then it will come back.

She took it a small shop and they sead it was in the evack (sp) system and there were too many things to start replacing.


HELP

EVAP systems suck, thats why I like my OBD-1.

[Heybo]

OBD-II is much better and easier to diagnose. It's just easier in person than over the net!

[chucked]

Originally posted by Heybo
OBD-II is much better and easier to diagnose. It's just easier in person than over the net!

LOL fix this one "EVAP emissions control system leak (small)" FYI that hole can be as small as a pin hole. I put hundreds of hours into my pos neon trying to fix it, thats why I bought the truck I have now, I gave the car to my sister.

[Heybo]

His problem doesn't sound like an evap leak. An evap leak shouldn't effect the running of the car. The most common problem for a small evap leak on Chrysler products is a defective gas cap by the way.

His problem is most likely going to be a carbon build-up in the intake, egr track, or IAC. It could even be something as simple as the a/c is low of freon and he is noticing the compressor cycle off and on. The check engine light may or may not have anything to do with his problem.

[chucked]

Originally posted by Heybo
His problem doesn't sound like an evap leak. An evap leak shouldn't effect the running of the car. The most common problem for a small evap leak on Chrysler products is a defective gas cap by the way.

His problem is most likely going to be a carbon build-up in the intake, egr track, or IAC. It could even be something as simple as the a/c is low of freon and he is noticing the compressor cycle off and on. The check engine light may or may not have anything to do with his problem.

wasnt the gas cap, btw, car cant have a check engine light to pass emmissions.

[Heybo]

Originally posted by chucked
wasnt the gas cap, btw, car cant have a check engine light to pass emmissions.

Just making a suggestion about the gas cap.

He didn't state where he was located and alot of states don't have an emmisions requirment test. I was just helping with his driveability problem and he hasn't told me what codes he has yet.

[chucked]

Originally posted by Heybo
Just making a suggestion about the gas cap.

He didn't state where he was located and alot of states don't have an emmisions requirment test. I was just helping with his driveability problem and he hasn't told me what codes he has yet.

I know, i was just giving my situation, and why I like OBD-1 better.

[pistonbone]

Maybe try running some seafoam through it.

[chucked]

Originally posted by pistonbone
Maybe try running some seafoam through it.
Seafoam is the ****.

[Heybo]

Seafoam MotorTune works great, but it won't clean the egr. You have to take it off and clean it and use something like a coat hanger and small wire brush to clean the intake port underneath.

[Crazy Honda]

When does it do it? after its warm? try this take out the thermostat run it see what it does if it quits then its time for a new thermostat.and if that don't work try the sea foam.:confused:

[chucked]

The problem here is that the shop they took it to know's what the problem is, they know that parts of the evac system need replacing. Seafoaming it or taking out the thermostat arent gonna fix the parts that need replacing.

[pistonbone]

Originally posted by chucked
The problem here is that the shop they took it to know's what the problem is, they know that parts of the evac system need replacing. Seafoaming it or taking out the thermostat arent gonna fix the parts that need replacing.

Start replacing.

[red2004 TRX450R]

Originally posted by red2004 TRX450R
Pulsating RPM’s HELP

I know some one that has a late model 4.3 blazer. And a lot of times when you are just going down the road the RPM’s with start dropping down and up like a 1000 RPM’S.

EX going along at like 3000 then drop to like 2000 then back to 3000 and so on……… like every ½ second.
It will do it for a wile and them it will stop and then it will come back.

She took it a small shop and they sead it was in the evack (sp) system and there were too many things to start replacing.


HELP

WELL I ROAD IN IT AGAIN THIS WEEKEND AND ITS NOT MOVING LIKE 1000 rpm MORE LIKE 2 OR 3 HUNDRED RPMS

thanks for the replies ill try the cleaning the egr.