1996 Chevy Tahoe running rough

[norcalstrokin]

okay so I bought a 1996 Chevy Tahoe two days ago from one of my buddies for $500.00 bucks! I ran a scan on in and it pulled up some codes. which are:

P0135-o2 sensor heater circuit bank 1 sensor 1

P0507- idle air control system rpm higher than expected

P1406- egr valve pintle position circuit

P0305- cylinder 5 misfire detected

so I just want to know where to go from here and what to do first and too see if there's any write ups I haven't searched the forums but ill do some searching on here too. I would be doing my own work on it. thank you for any advice you guys give me!

 

[lesterl]

WOW!!!! $500 lucky dog.....

P0135 Sounds like a possible bad O2 sensor, ohm out the heater circuit and check fuses.

P0507 Possible vacume leak? Bad IAC valve?

P1406 Wiring issue, bad EGR valve?

P0305 Plugged up injector? Possible candidate for a MPFI upgrade install.... (GM part).

 

[norcalstrokin]

thanks for the response! yeah he didn't know what was wrong with and didn't want to deal with it so I took it off his hands! lol the body on it is rust free which I bought also. so just got to get her running right I don't want to drive her the way it is now. so I am trying to figure this out I am going to change all the spark plugs and wires and all the sensors that it pulled and then go from there and see if that will fix the misfire that it has before I go and get the MPFI upgrade install. I read a little about doing the upgrade but I had some questions about doing the upgrade I found the part on amazon which is a Delphi brand is it any good? what other parts would I need to the upgrade? I am sorry for the long post.

 

[lesterl]

Delphi is good. I have never done one of the upgrades personally (I have a 95 which is TBI, and my 96 Sierra never acted up....)

Might try to seafoam the intake, run it around and get everything up to temps and pull the brake booster line with it running (in park) and pour (slow enough so as not to stall the engine till the end) some Seafoam down the intake.

Put some Seafoam in the gas tank on the next fillup....

I would get the codes cleared and see if any come back after all that....

 

[norcalstrokin]

oh okay I think ill give it a try after I get all the sensors switched. I was able to get all the ones I needed and some for 100.00!! got lucky on that one! lol I will also be changing the spark plugs and wires and see how it is going to be running after that and if its still acting ill try the seafoam stuff. what exactly is that? I did clear the codes the codes but I haven't taken it on a test drive but it is now only pulling up one code which is:

P0300- random/ multiple cylinder misfire detected

once i get everything switched out i will take it for a test drive and see if it still acts up and pulls any codes.

 

[norcalstrokin]

this is the new addition to the family thought i would post a picture of it sorry for it being so large but it doesn't have any body rust just minor scratches! but not bad for 500.00!!

 

[lesterl]

Your killlin me dude. Love the truck, but I think swapping out a fistfull of sensors for junkyard ones is a stupid idea.

First of all you dont know if they are good. Perhaps if you would test them before you installed them it wouldnt be so bad, but then agian, why not just test the ones that are in the truck already and only replace what is bad?

Man you are gonna create more stuff to chase around if you arent careful...

Dont take this post the wrong way, I have just seen this scenario several times and it usually involves more money and time than if it were troubleshot the right way.

If you want help testing something ask, If I dont know I am shure someone on here could help also......

Just my 2 cents...

 

[norcalstrokin]

Lol I should have said that im only swaping out the ines it needs and juse kepping the other ones untill they are needed but there are all brand new sensors from BWD. Yeah I am.not trying to do that. Lol its my.first gas rig so trying to make it last. Lol oh of course not your just trying to help me out so not taking it the wrong way. I sure will be asking a lot of questions. Like idk how to change the spark plugs and wires. Lol I've never had to do it since diesels dont have any. Lol thanks for your advice tho.

 

[lesterl]

Glad you are being sensible then..... Spark plugs are easy on these (are on my 95 at least, I just installed an Accell Coil and regapped my NGK's from 35 thou to 45 thou..... Soot in tailpipe is all but gone now......

 

[lesterl]

As far as changing out plugs, when you take them out look at them real good, inspect coloration of the ceramic, deposits and such, they will tell you alot about the condition of the engine and each cylinder. Go with a single electrode Platinum from Either AC Delco or NGK. When you pull them engine cold. When reinstalling thread in aways by hand then snug them with a socket wrench. I did all of mine with little more than removing the snrokel on the air cleaner...... very easy to get to. Yours may be a tad more stuff as mine is TBI and yours is CSFI.

 

[norcalstrokin]

the spark plugs that I got were e3? are those any good? sweet ill make sure I check them out when I pull each one tomorrow and see how they are a buddy is coming over to help with that I am not trying to mess anything up. lol i tried switch out the o2 sensors but i couldn't get the nut to break lol any tips in trying to get them out? i cleaned out the throttle body that was gunky but all cleaned out.

 

[lesterl]

I am not that familiar with the e3's, have heard of them, just no experience.

As far as the O2 sensor, heat the bung up with a torch pretty hot and get a decent pipe wrench on the sensor itself......

The TB does get a ridge of carbon in it and if you dont clean it out after a while the throttle will stick and snap open fast when you go to take off causing you to lunge forward.. Glad you cleaned that.....

Matter of fact seafoaming the intake would probably be a good idea....... Search for that, alot of guys have done that and done some drastic improvements in ops...

 

[norcalstrokin]

I switched out all the plug and wires, changed out the IAC valve and EGR valve.the only code its pulling up now is the cylinder 5 is misfiring still. I took it for a test drive but it was only like 7 min. I will take it tomorrow for a longer drive and see what happens. will be adding sea foam to it and see if that helps. it still revving up when I take it out of drive but when I put it in drive it goes back to regular rpms you would say. it seemed like it didn't have any problems when I would floor it and would accelerate but when its in park you an tell it has a misfire. I still couldn't get the damno2 sensors off hopefully tomorrow will be different tho. lol


when I had the TB it looked black and gunky in there so I went and bought the seafoam and see if that helps anything.

would this work to do the conversion to the new fuel system?
thank you for all yourhelp you have been giving me.


http://www.ebay.com/itm/One-Brand-N...Parts_Accessories&hash=item5d3ffec9b0&vxp=mtr

 

[lesterl]

that looks like the one.... I would seafoam the intake real good first.....

Get the engine up to operational temps by driving around a bit. When you get back, park it, but let it idle. Remove the vac line to the brake booster. Slowly pour about 2/3 of a can of seafoam down the line and then when that is gone, upend the rest into the line to stall the engine. Let soak for about 10-15 min, then restart (will be hard to start) and let the smokey fun begin.....

This may free up the injectors for ya..... if not you only wasted a few bucks on a can of seafoam, and then your intake is all the cleaner for the MPFI upgrade...

 

[norcalstrokin]

okay sounds good! I will be getting if it sea foam don't work. but the neighbors should have a good laugh. once I try this I will post results. I also notice that the oil gauge doesn't work the way it should be it only works when you give it gas, so I well also be changing out the sending unit sensor and see if that makes it work right.

 

[lesterl]

What does the oil guage do? Go from none to 1/2 scale +?

Oil pressure sensor is on back of block under distributor.... have fun.... I would put a new one in there if it were me.....

 

[lesterl]

What did the plugs look like?

 

[norcalstrokin]

well the seafoam didn't work it still has the misfire on cylinder 5. so its time for the MPFI upgrade I get the part tomorrow. lol I really hope that gets it fixed. with the upgrade will it still use them same injectors as before?

yes the oil pressure goes too about half way and then slowly drops down to 0 and stays there but if I give it gas then it goes up a bit but then goes back down.


three of the plugs were a little carbonated but all other seemed fine.


what fuse controls the unlock and window buttons?

 

[norcalstrokin]

I forgot to say that there is a delay in trying to start it.

 

[norcalstrokin]

after the delay in starting a couple of seconds I would say it revs up to over 2000 then goes back down and seems to idle fine I think and then when I put it in drive or any gear other than par it seems fine but when I put it park it rev up past high and then lower itself back down.