89 K5 Blazer low idle/ surge problem

[doop300]

Hello

I just got a 89 fullsize blazer and its got some surge/pulse thing going on as I drive it and at idle, which seems to be kinda low. When your driving in overdrive and the engine is more or less at idle it kinda pulses back and forth. At a stop it seems like it wants to die and accelerating from a stop it surges but then stops when you give it more gas. Ive replaced the fuel filter but would like to know what I should do next before I spend a lot of money that I dont need to.

Any info would be great.

Thanks

[MT-2500]

Originally Posted by doop300

Hello

I just got a 89 fullsize blazer and its got some surge/pulse thing going on as I drive it and at idle, which seems to be kinda low. When your driving in overdrive and the engine is more or less at idle it kinda pulses back and forth. At a stop it seems like it wants to die and accelerating from a stop it surges but then stops when you give it more gas. Ive replaced the fuel filter but would like to know what I should do next before I spend a lot of money that I dont need to.

Any info would be great.

Thanks

If it is doing things like that always check the tune up secandary ign system?
Any check engine lights on?
Can you feel a dead cylinder miss?
When was the last tune up?
Good AC plugs?

[doop300]

The service engine soon light comes on at startup but then goes off, so Im not too worried about that. Other than that everything is good, recent tune up and everything is in order and where it should be.

[MT-2500]

If everything was in order and wher it should be you would not have a problem would we.
We can not help if you do not help yourself.
Can you feel a miss?
Good AC plugs?
HAVE YOU CHECKED FOR CODES?
Good hot blue spark to all plugs?
How many miles on cap and wires and plugs and fuel filter?

[doop300]

I found the problem! It was the fuel presure regulator inside the tb. the spring was rusted in two and the diaphram was covered with rust, guess theres a lil water in the gas. So its running much better now, but still wants to die sometimes at a sudden stop.
Im thinking the next step will be to pull a plug and see how they look and go from there.


How do you check codes?

[doop300]

I put a new cap, rotor, wires and plugs in and a new egr sensor/ selinoid. Still having the same problem but it does run stronger now. Replaced the fuel filter. Not sure where else to go with this blazer.

[MT-2500]

Originally Posted by doop300

I put a new cap, rotor, wires and plugs in and a new egr sensor/ selinoid. Still having the same problem but it does run stronger now. Replaced the fuel filter. Not sure where else to go with this blazer.

Go back and read and answer post 4.
To check for codes connect pin A&B together on diagnostic connector.
Countslong and short flashes on check engine light.
Post back.

[doop300]

Cant feel a miss but with the surging its hard to tell. Good plugs and no codes. Have yet to check the spark. Theres about 20 miles on the cap and rotor and plugs and wires and about 30 miles on the fuel filter.

[Ravhat]

You said that you changed the egr senser/solenoid, you may want to change the egr valve. check the valve by pressing up on the underside of the diaphragm, if it moves freely and does not stick or bind it should be fine, but a bad egr valve will cause low idle speed stalling and surging at low speeds. make sure you check all your vacuum hoses also. Hope this helps.