Idle up and down!!!

[abignwtn]

Hi, I am new here I was wondering if anyone has experienced this before. I have a 94 blazer 2wd CPI motor. WHen it is cold in the morning I let it warm up enough to leave then when I put it in gear reverse or drive it wants to go on its own. I can take my fot off the brake and it will go on its own. Then when it warms up and I am at a red light it will shudder. Then if you put it in park it will rev up and down. I think I might have narrowed it down to the Idle Air Control...possibly. I have owned Fords before and they are notorious for it but are more noticable when acting up. I have put my scanner on it and it shows a IAC error and a EGR error but neither one every time. When I go into the scanner and check all the sensors a few of them are out of spec but within range. However the EGR and IAC are a good ways out. Anyone have any ideas.

[abignwtn]

Also the SES light is NOT on. Like I said though I can still pull those two codes sometimes. The SES light does work though I have tested it.

[abignwtn]

Sorry I keep forgetting things...I have replaced the TPS already also I did that when I first got it a few months ago.

[Big Mack Daddy]

sounds like iac or maf sensors to me

[abignwtn]

Thanks for your input...that has been my thought the whole time...but I have talked to a few people and they are saying I didnt install the TPS right...there is really only one way that I can tell anyways to install it.

[csl2006]

my maf sensor has 2 codes thrown and runs fine =/. check your vaccuum lines.

[abignwtn]

That and also I dont have MAF (94 CPI). I have checked the vacuum lines and can not find anything out of the ordinary. I am still leaning towards the IAC. We will see maybe after the Xmas rush I will have some spare change to get it and replace it. More ideas are still welcome til then...

[csl2006]

hope you get her all fixed up.

[12sws27]

Maybe you can replace the IAC and try cleaning the EGR valve. Thats probably what I would do. Unless the IAC was pretty expensive then I would try to clean them both with tb cleaner:D

[abignwtn]

Yeh I mean the IAC isnt bad its like 60 bucks wholesale price. I have seen some ppl on here saying it is like 40 or less...I live in Georgia and everything must be more expensive down here now...lol

[abignwtn]

Ok...I put the IAC on and it is better on the stubling and it doesnt want to go on its own anymore...however the idling up and down is still there...maybe a vacuum line...maybe I got a bad TPS...MAP sensor maybe? Any help would be appreciated...

[spideyjected]

Pull the egr valve out and clean it really good. Maybe the carbon build up is doing it. Fuel filter too.

[12sws27]

I would think its a vacuum leak. Do you hear any hissing noise?

[Jongo88]

I think it it the tps... I went through all of this. I put a brand new tps on and all this stuff started. I put a used one on and it run's good now. I replaced the iac and that was NOT the problem. If you buy a pos from Advance or a place like it you will have problems. try to get a AC Delco one. Just my 2 cents.. I hope this makes sence... I'm drunk....

[abignwtn]

No I dont hear a hissing noise...I HAVE checked all the vacuum line...I know that doesnt mean I cant miss it BUT I did check them...I am thinking TPS again...I put a Borg Warner TPS on...today I put an AC Delco IAC on so that shouldnt be an issue now...but the TPS is bugging me...Also like I said in my original post at one time the computer was saying EGR error..cant remember the P# but that was with my Matco scanner...I know these CPI engines are supposed to be hard to deal with...but I thought that was mainly the fuel injection...the guy that I bought it from has replaced the CPI unit and the FPR...so I dunno...with all that said anymore suggestions? I will try to clean the EGR tomorrow see if that makes a difference...maybe throw a fuel filter on too...we will see...

[Cameo_S10]

Trial and error. Maybe he was having some of the same problems.

[Jongo88]

When you pull the egr valve off install a new gasket with a screen. That way you won't have any more problems with it getting clogged...

[abignwtn]

I will do that

[abignwtn]

Did not get around to the EGR or fuel filter today...it ran good all day though...no idling up and down...until I was coming home from work...then it started it...so now it is intermittent...I could tell by the way it was running and shifting while driving home...got home put it in park...sure enough started idling up and down...I just cant put my finger on it...I will see maybe tomorrow I can get the EGR off at work...I am still leaning towards the TPS again though...

[bespurcell]

Hope you find the prob.

[Jongo88]

I'm telling you I had the same problem... It was the tps. If the egr is clogged it will not idle and run realy realy bad...

[spideyjected]

I'd listen to John, he's had just about everything go out on a CPI that can. Except of course the fuel pump! His fuel pump has a ton of miles on it and still works.

[Boatz]

I am eager to see what your fix is. My 00 is doing the same thing intermitantly. For really great prices on Delco stuf (used) I have a guy on ebay that I deal with. I am sure I am not the only one. S10wharehouse.... I get most of my stuff from there..

[abignwtn]

Ok...have been working alot lately but did get around to doing the EGR...Helped some but still idling up and down...so...I am going to get a AC Delco TPS...the shop i work at can get Delco stuff alot cheaper than dealer. So give me a few days and I will try to get one. Thanks John.

[abignwtn]

Got the Ac Delco TPS and did a tune-up with all AC Delco parts...runs like a top now...hopefully it is good. Thx for everyone's input.

[Jongo88]

I'm glad it all worked out for you. The good thing about the cpi is they all do the same things. I have learned alot about them having so meany. Sounds like your good to go.....

[spideyjected]

So all along the problem with CPI has been that the owners of the vehicles didn't take the time to get to know them!

[hero dave]

its all fun and games till it starts running like CRAP!