Help 4.3 all messed up

Well this is what ive done. Plugs not bosch, wires, rotor, rotor cap, throttle position sensor, Pcv valve, CPI unit (the passenger side was golden and clean, replaced the oil it was almost like i was drainin gas it was nasty), fuel filter... What else do i need to do to make this thing run better.
It runs with codes reading random multiple misfire, feels it too. what should i do??? HELP PLEASE.

Oxygen sensor...
Give that a try.

What year?

Are the misfires at idle only or during driving?

Did you do a Throttle Body service?

Did you try cleaning your IAC?

Well this is what ive done. Plugs not bosch, wires, rotor, rotor cap, throttle position sensor, Pcv valve, CPI unit (the passenger side was golden and clean, replaced the oil it was almost like i was drainin gas it was nasty), fuel filter... What else do i need to do to make this thing run better.
It runs with codes reading random multiple misfire, feels it too. what should i do??? HELP PLEASE.

Hello! What year do you have?

1.) Have you removed your EGR Valve and checked for chunks of carbon keeping the pintle open? <----Important

2.) Does the exhaust smell like rotton eggs?

We need to know the year before I can continue, I need to know that to see if your vehicle is computer timed or not.

Post back soon and remember next time to post ALL information.

Ok here it is its a 1995 4x4 LT 4 door vin (w) sorry bout not having all the info on my first post. The EGR valve was recently replaced and i took it off yesterday afternoon. not so sure but the other day it smelled like candels burning but that smell is gone so thats bout it. thanks

it missfires at all times like it has something to do with the way it is gettin its info from the computer not so sure though

hey one more thing how important is the idle air control valve???

any have any pics of where the knock sensors are i cant seem to find them

Hold on their, please learn to edit your posts instead of adding a new post for one statement. Makes things confusing.

Please remove and check your EGR valve again and MAKE SURE that there is no carbon chunks sticking the pintle open.

Do not just ASSUME that it is fine because the valve was replaced. New carbon can be dislodged and this could happen several times.

Check it out and get back to us.

Just a thought, did the misfires occur after you changed the wires? Do you think that you might have two of them reversed or something?

The IAC or Idle Air Control is important! If it is not operating properly your engine would not hold a constant idle or perhaps not even idle or the idle could be too high. I have never seen a bad idle air create codes indicating a misfire, perhaps it could.

Again, did this misfire condition occur after you changed the CPI? Did you clean the hole of carbon prior to installing the individual injectors? Are you sure you seated them properly?

My '93 4.3 can be a bugger at times to get the cap seated, are you sure it is not cocked? Been stupid myself and did that once and it was misfiring.

Your second post you stated that you removed the EGR, you did make sure there was no carbon I hope.

I wouldn't jump the gun on the knock sensor.

Let's see, ummmm, your third post says it is misfiring at all times, I will assume you mean no matter what the RPM's are. So, I would forget the IAC for now and recheck your wires, cap, rotor and pulg gaping.

Good Luck! and get back

sorry bout the posts. OK i had the egr off yesterday and there was nothing blocking the pintel open. So what do you think i should do next. Thanks

Reset the computer by pulling the negative terminal for 10 minutes and try.

Who did this work on your truck?

Well ive done all the work on my blazer i have never taken my vehicle to a mechanic? actually none of my vehicles go to the mechanic. Also i am on a military base where we have an auto hobby shop that has four certified mechanics.

I guess that i could try to reset my computer tomorow after work. What will that do?

The next thing is... I had the problem before i changed my CPI I had it after also but it wasnt as bad like is was something else. Yeah no carbon build up or anything.

so now im gonna check my wires and rotor and rotor cap its the flat one with the posts coming out the side of it. Does anyone have the firing order for it maybe i got bad info from mitchell on demand who knows.

Ok thanks for all the help ill get back with all of you. If you all think of anything else you know what to do thanks.

Here's something, check the coil. Wait until it gets dark and look to see if it is arcing to the metal holder. Also, look to see if it has evidence of arcing. You may have to remove it but you certainly can look at it when it's dark.

I have seen this in the shop and it can be tough to diagnose.

Thanks for the info ill check that one out in the mornin before i go to work. If it is goin bad wouldnt something like that totally mess up everything. Well i guess that is what it is doin well thanks ill get back with you on the flip side.

Check your oil and see if it is high.

Also, reset your computer.

You HAVE to reset your computer to clear the EGR code if per chnace that is what happened.

Hint for all W-code owners:

with the engine running, if you suspect an evil or stuck egr, pull the brake booster vac line and hook a gauge (with adaptor) to it. Should read 18+, if it reads low, then the EGR is likely stuck open which might occur WITHOUT any carbon in it, the guts of these things get 'sticky' (and at $180+ a pop that sucks)

True, but I have yet to see one that sticks open without a piece of carbon in it.

Every other oil change you should remove it on a "W" engine and spray the inside of the valve down with throttle body cleaner and reinstall.

True, but I have yet to see one that sticks open without a piece of carbon in it.

Everytime other oil change you should remove it on a "W" engine and spray the inside of the valve down with throttle body cleaner and reinstall.

send me your email and I will send you the one I just yanked off a 95 a few days ago. Its an epidemic.

I will pm to you, I want to see this.

Sorry Blazer LT, in my '93 4.3 it is an LEGR, for those that don't know it is a Linear EGR. No vacuum line to it. In '95 I got a brand new one from GM because they had problems with binding of the inside shaft. The new one crapped out 10 months later. They gave me a new one. This one has been in there ever since without a problem. I also have a brand new LEGR sitting on my shelf that was given to me, however, it is for a '95 and it won't fit my '93 because they changed where the plug fits. I will have to agree with quaddriver.

The one thing is, you are dealing with a dealer that like to replace parts rather than clean and replace them.

I have had my EGR valve stick open 6 times and all that it took to fix it was to remove the carbon chunks, spray the inside down thoroughly with TB cleaner and reinstall. Then reset the computer and it is done.

You don't have to replace the valve everytime!

First of all, I didn't have the dealer do the work. I removed the LEGR and the damn thing was open with no carbon in it. I performed all the tests as spelled in the Mitchells motor manual and it failed. Wouldn't budge. I took it to the dealer and he said that there was a recall on them. They gave a new one free of charge after filling out some paper work for the warranty on the part. Ten months later it did the same thing. Took the LEGR off and it was all the way back and you couldn't get it to move, again, like the first one. Went back to the dealer and he said no problem, Emission components were guaranteed for 12 months. He gave me a new one, I installed that one and have not had a problem. That is what happened. I am not a shotgun enthusiast when changing parts, especially very expensive ones.

Did you spray cleaner into it at all?

Yes, I had douched the first one I removed with 2+2 but there wasn't any real carbon build up like you would expect. After hooking the LEGR back up to the harness but not mounted, and turning the key on, the Mitchells motor manual said it should seat. It didn't. It mentioned a few other things to check including jumpering something but I can't remember, it was 9 years ago and since I hit 50, the brain don't remember as well LOL. I soaked it with PB Blaster but to avail. I went to the dealer to buy one and they informed me of the recall. The second time I replaced it, it was like the first time. Since it came with a 12 month warranty I just took it back.

Ah, yes, in that case, yea, guess something was jammed in it.

Mine were never stuck, just stuck open with a pea sized ROCK of carbon.

Guess by '95 GM maybe, just maybe, finally got it right. LOL

I own a 95 Blazer.

quaddriver, got those pics yet?

sent

well hey there sorry for not being able to get back online ive been real busy with ivan the great (hurracaine) Well i found signs of arching within my distributor. The mechanic that had put the cap on last, didnt tighten it enough and so there was a real bad arching to the screw that held it down and there also was a major melting point within the cap it was real bad like it was bout to catch fire well its still running real bad. So i am taking it directly to the GM shop and throughing in the towel thanks for all your help ill get back with you all to give you an update. Once i get this taken care of im throughing a 3 inch body lift and new jet black rims and 33x15x11.5 in BFGs MTs. will have pics avalible should be done in the next month or so

Jeez, just put a new cap and rotor on and continue.

Had the same problems with my 92, did everything everyone said above then replaced the Oyygen sensor on the muffler and fixed everything. I also was told that it could be a leak in the fuel injection system?? Thankfully I didn't have to go any deeper Good Luck!