Hey Guys having couple issue wanted to consult the "experts".

1. Check engine light "flutters" on every once in a while. Usually while driving between 70-80mph. Uusally only for a few seconds. If I back off the gas it shuts off. ( I live in one state and work in another during the week so it usually happens during my 358 mile "commute" in the middle of east bumble South Ga). I've got normal oil pressure, recent alt (again), recent tune, recent new cat back system. Any ideas or should I pick up the $24 code reader at Wal Mart and check out the stored codes??

2. MPG are really suffering. Was thinking after recent complete tune up ( plugs (truck plugs), wires, cap & rotor) and fairly recent new cat back system that maybe my cats are finally clogged up ( almost 200K miles now). Truck still has enough power for me but has definately lost some "grunt". Have read some post on this issue. Gonna set me back about $190 to get rid of the pre-cat and cat and replace with a Random Technology hight-flow cat. (You know me found a good deal on the internet).

Your feedback is appreciated!

 

I've found that an o2 sensor that is beginning to go bad can cause similar symptoms. The resistance my be changing and causing poor economy and performance and at the same time the computer may recognize it as still being within tolerance. Just a personal experience. Hope you figure it out

 

I agree, sounds like the O2 sensor is crappin' out, you can test it, look in your handy Haynes or Chiltons manual for the procedure, you will need a multi-meter. Both of those symptomatic of HEGO failure (O2 sensor). Also you can check the saved codes by reading the test through the check engine light which is also explained in the manuals. It is an OBD I system, so you don't need a scanner to check saved trouble codes. Once you retrieve the codes, you will know for sure. Good Luck.

 

take it from experience , i wouldnt start buying parts and throwing at it . been there done that and your issues could be alot of things . check the codes , if you dont have a book explaining how it is done with out the reader then it is well worth the small amount for one . the O2 sensor can be screwed up if tested (if it is a certain type ) so unless you know which type you have dont start disconnecting wires and testing for ohms resistance , again unless you have a book explaining this .
Check your codes KOEO ( if your check engine light is flickering then it is more then likely storing codes )and go from there starting by eliminating the first code and then retesting as you fix each one ( some times one code leads to another code so fixing one may fix others as well ) . Let us know what you come up with ??

 

Thanks alot !

I'll start with the codes and go from there....maybe this will answer both questions....Have thougt about the code scanner on more than one occasion.

Will post a follow-up as soon as I find something out.

 

Well picked up the scanner this weekend finally and it scans the following :

111 111 111 111 111 111 = 33

EGR - not closing completely I think ( left the stupid book out in the truck).

then it gives...

1

and then

111 111 111 111 111 111 = 33 again?

this was after a following the proceedure to clear all codes after first scan with following results:

111 111 111 111 111 111 = 33

111 111 111 111 111 111 11 = 332
111 111 111 111 111 111 11 = 332

book advise to clear codes to make sure reading was true. I had also found on of the "tubed" connections just below the EGR was not connected. ( Prayed alot that this was my problem but NOT!)

Book says first code is Hard Code and following are Stored Previous codes ...or something like that.

Also alittle worried about just how rusty the EGR connections are. Especially the LARGE pipe running back down to the manifold.

I've also seen other post about completely blocking off the EGR and am a bit confused about this with all the computer/sensors on this truck.

Sorry for long post... All advice is welcome...

 

It's not a good idea to disable the EGR.

If you look in a repair manual it may give you instructions for cleaning the EGR. Usually chunks of carbon get stuck in there and keep the valve from seating all the way. Usually you can take the valve off and clean it then start the truck up with the egr valve off and rev it up a little to blow all the crap out of the EGR tube. But it all depends on the codes your getting and whether or not you think you can disconnect it without breaking it since it's all rusty.

BTW i think code 32 is for EGR valve not seated and code 33 is for EGR valve not opening, which could be an egr valve problem or something with the vacuum lines or vsv's.

-Jon

 

or the egr position sensor not within tollerances and giving false readings . clean it up as F4E suggested then possibly use a vacuum pump on it to see if the codes go away . if the do then it is also possibly the evr ( egr valve relay by the coil ). or possibly a vacuum leak.