89 S-10. rough idle..

Hey Guys..
I really need alittle help here..
First off this truck is an 89. 4.3L, automatic, 4x4. roughly 114,000 miles on it.. Rebuilt the engine at 84,000 miles..

About 2 weeks ago when I was driving my truck home. As I approached a hill. the thing started to jerk, backfire, loose power, etc. It sounded like a bunch of fire crackers going off under the hood.. So, when I got home, I took my old coil and put it back on. (I'll explain later on why I did that)

Well, that seemed to fix the lost power problem but it seems like it created another problem as soon as I started the truck.. Now, I have a rough idle.. The SES light will come on about 4 secs after you start it, flash once and then it's on all the time..
Yesterday, when I was driving it.. I shut it off to go inside a store and when I came back out about 10 mins later and started it. The ses light was complety out, it ran really good til I came to a stop light like a mile away.. When I went to pull out, It really jerked all over the place, couldn't get nowhere.. lost power, and when I finally got through the stop light and pulled over.. it stalled out. Well, when i started it up again, the ses light came on, had my rough idle back and it ran ok coming home..

Now the reason why I put my old coil back on was because, back in feb, I was having the lost power going up hills.. so, I went ahead and replaced, the spark plugs, wires, 02 sensor, map sensor, cleaned the egr valve up, and put another used coil on it.. (I had a spare coil) Well, one of those things fixed the problem and it was running great til about acouple of weeks ago.

I have sinced replaced the spark plugs again, put a new dist cap & rotor on, and tried another 02 sensor. Still a rough idle.. There is no miss..

Could it be a coil problem? My dad saids it sounds like a coil problem since the fit it took yesterday..
I even thought that I got bad gas and went and changed different name brand gas.. I still have the rough idle..

I'm thinking about buying a new coil on Thurs. and giving it a try.. Both the ones I have are used..

Can you guys offer any kinds of suggestions?

Well, Thanks..

Got any codes?
If so post back code no.
Do you have good hot blue spark to all plugs?
How is dist cap and rotor and plug wires?

well, first off, I don't know what you mean by codes.. Sorry..

The plugs are all brand new. I replaced them about two weeks ago.. The dist cap & rotor I put on sunday afternoon.

The plug wires are all in pretty good shape. Replaced them back in feb when I did the tune up..

I'm gonna buy the coil today and see what it does.. Hope I get lucky..

well, first off, I don't know what you mean by codes.. Sorry..

The plugs are all brand new. I replaced them about two weeks ago.. The dist cap & rotor I put on sunday afternoon.

The plug wires are all in pretty good shape. Replaced them back in feb when I did the tune up..

I'm gonna buy the coil today and see what it does.. Hope I get lucky..

You need to make sure you have good hot blue spark to all plugs.

Codes = check engine lights.
Different codes for different problems.

http://www.troublecodes.net/GM/

ok.. I went and bought a new coil yesterday and that wasn't it.. Still my same problem.. I'm just stuck with a spare coil now..

I might just buy a new set of plugs because I honestly don't know how to tell if I have a blue spark to all my plugs unless, I lift the hood at night while it's running?:dunno:

I went out and hooked a piece of copper coated wire into the data link connector, this is what I got.. I got a 12, 13, 13, & 14. sometimes, I got a 11 but, the other ones kept flashing the most.. Now, are you supposed to take these numbers and look at each one seperate like look and see what 12 is or are you supposed to add all these numbers up and see what it is like all total, the numbers came up to 52 or perhaps 63?

This is my first time doing this so, I honestly don't know what's up.. Did I do it right? I kept counting the flashes. and went with the site directions.. which thanks for the help there.. I appericate that....

Also, it didn't have my engine listed for my truck... At least not for a 89. I looked into the 92-93 section..

Well, thanks again for the help so far..

To check for spark pull plug wire and check for spark jump out of the end of it .
It should jump 1/4- 1/2 in with a good hot blue sppark that has a good snap to it.
Also check for spark to all plugs.
You do not add codes.
Just the long and shorts together,
Your codes says you have a tempt sensor problem on code 14.
Which coould cause hard start.
12 may be a pass code.
Code 13 is a O2 sensor problem but does not cause no start.

Ok.. I know what you mean now.. It's the same concept that I do on my push mower.. I understand..

back around the middle of may, my truck was over heating. actually the gauge went up to 260 shortly after you started it up but about 5 mins later it went back donw to 210. That when I got a thermostat and put in.. I no longer have the over heating problem but, I'll see if I can find that sensor.

I'm not really having a hard time starting it.. it was just that one day when i switched coils to see if it would run any better which it hasn't.. When I go to start it, it'll run really good for about 4 secs then when it backs off, the rough idle will start and the ses light will come on.. I'll try another 02 sensor and see what it does.. maybe the one I bought is a bad one..

Oh... would a valve problem cause a rough idle? Just wondering..

Ok.. I know what you mean now.. It's the same concept that I do on my push mower.. I understand..

back around the middle of may, my truck was over heating. actually the gauge went up to 260 shortly after you started it up but about 5 mins later it went back donw to 210. That when I got a thermostat and put in.. I no longer have the over heating problem but, I'll see if I can find that sensor.

I'm not really having a hard time starting it.. it was just that one day when i switched coils to see if it would run any better which it hasn't.. When I go to start it, it'll run really good for about 4 secs then when it backs off, the rough idle will start and the ses light will come on.. I'll try another 02 sensor and see what it does.. maybe the one I bought is a bad one..

Oh... would a valve problem cause a rough idle? Just wondering..

Needs some proper testing before throwing parts at it..
Check for good spark to all plugs.
Check for cylinder miss.
Vacuum leaks and egr valve stuck open.

Check engine vacuum reading at Idle and at 2K rpm and post back readings

Hi..
I got another 02 sensor and it seem to have fixed the rough idle.. I test drove it yesterday and It's running alot better now..

Now, I got this little problem.. When you go to stop. the engine sounds like it's going to shut off but, then it'll pick right back up and run smooth.. It'll do it about every 3 to 5 sec. If you run it, you can't notice a thing.. It actually runs really good once you get going..

Could it now be a miss?

Thanks..

Hi..
I got another 02 sensor and it seem to have fixed the rough idle.. I test drove it yesterday and It's running alot better now..

Now, I got this little problem.. When you go to stop. the engine sounds like it's going to shut off but, then it'll pick right back up and run smooth.. It'll do it about every 3 to 5 sec. If you run it, you can't notice a thing.. It actually runs really good once you get going..

Could it now be a miss?

Thanks..

You need to check it out.
Go ove the thingssuggested in upper post.
Also clean tbi and iac valve and egr valve.

Any codes now?

i got a 92 blazer CPI v6 4.3
tested the fuel pressure today and when i just had the key on the pressure when up to 10 psi then dropped right away
started it and it went up to 54psi and stayed there
its hard to start (usually takes a few seconds)
and after about 15mins of driving it, it bogs down and loses power
all i have to do is pull over and restart right away and i goes for another
15 mins
what do u think???

i got a 92 blazer CPI v6 4.3
tested the fuel pressure today and when i just had the key on the pressure when up to 10 psi then dropped right away
started it and it went up to 54psi and stayed there
its hard to start (usually takes a few seconds)
and after about 15mins of driving it, it bogs down and loses power
all i have to do is pull over and restart right away and i goes for another
15 mins
what do u think???

I think you need to start your own New Thread on your problem.

That sure will save on the hi jacking some body's else post and on hi jacking bills.

Well, I figure I would stop by and give you an update. I still haven't got the truck running right yet. I went ahead and got a good set of ac delco spark plugs and that didn't fix my problem. It's actually getting to the point that when I stop, I have to keep one foot on the brake and the other on the gas just to keep it running. It just has a rough run to it..

When it's cold and I go to start it up, I get the ses light. That'll stay on for about 30mins til either when you shut the engine off or it'll go out on it's own. I pulled the neg batt cable off twice to reset the comp and I keep getting a code 12 & 42. Those are the only two codes so far..

My dad has a compression tester and one of these days, I'm gonna see if he'll help me see what the compression is supposed to be in the cylinders but, i don't know what the readings are supposed to be.. is there a site out there that I can compare the numbers with whenever I do get it?

Tom afternoon I'm gonna pull the egr valve out and clean it up and put it back in.. Just to see if it improves any.. I don't want to go buy a new one and find out that it's not it.. I can't keep spending my money on stuff that I think might fix it and it doesn't.. It's getting expensive..

Something relatively inexpensive to replace would be the O-Rings on each injector. A worn, cracked, or chipped O-Ring will cause strange fuel related problems.