Hi guys.


The family and I went on a great tip to see my parents in the mountains of North Carolina. We took the van and it performed well. It was great to have and we love traveling in it. A quick observation is that we traveled on some extreme roads and I was loving all terrain tires. I was glad I had them. If I had my old highway tires, there would have been a lot more slipping.


I was actually satisfied about the way my tiny 3.9 performed. The only slow period was going up a 3 mile 7% grade. I had it at WOT and was going 60-65 - LOL. Sure, some of the roads in NC are way over 10% and it was doing 30, but on those roads, that is all you want to do. The other times I was doing 70+ with ease on the interstate. A lot of times, I was running at 3320RPM...yea...


Being back in FLA, now I have noticed an issue that just popped up. I have some symptoms that make me feel about the way I am thinking. But, I may be on the wrong track, and I need some help with that.


During the trip, I was using the HVAC a lot more than I usually do here in FLA. I had three times where I had to let my foot off the pedal to get the blend door to move from floor to register. I thought maybe being at 3000+ft that elevation had something do with that or it was just erroneous. After running at 3000 RPM for 10+ hrs, I noticed a few backfires on acceleration. WOT throttle in the city on the way home would cause, what seemed to be, a retardance of spark and then backfiring. It didn't do it ever time, but was something that hasn't ever happened. Also, I checked oil when I got there and found I used a quart. That was an usual occurrence too.


I keep up with maintenance. The CPS, coil, plugs, ceramic boot wires, rotor, cap, filters and fluids are all great. There are no codes, or electrical issues. All systems are GO.


I have been thinking about the above issues and went through various backfire symptoms lists and don't see anything that really coincides. I do have some theroies. My first is my belly pan gasket went. Another is I burnt the O2 sensor. Another is I think that the long run(s) caused carbon to dislodge. The van now starts, runs and with normal soft throttle operation is good. I am just wanting to start diagnosing what is up. I am unsure how to check vacuum in this situation. I guess I would need a vacuum gauge, but I am unsure where it would go. I also don't want to run down a rat hole.


Thoughts? Thanks guys.

 

I think I know the hill you are talking about, I towed a car up that hill with my van and it was slow going.

My first thought is that you need a tune up. Have you pulled your spark plugs out to confirm they are OK or are you guessing they are OK based on mileage?

Regards, Steve

 

I checked a couple of plugs and they look very nice. They are hardly worn.
I also got a mirror and looked down the throttle body into the bottom of the intake...it was dry. There was no oil or even slight residue...I think this rules out the belly gasket. I also used no oil on the way back. I was using 5/30 - maybe that is too thin for the stress of going up at high speed ???


The van ran fantastic today. I did a few jack rabbit starts and had excellent acceleration (for what it is ) and no backfiring. The AC vents had no issues.


As for the mountain, I was going west on I26 out of Spartanburg and going to Asheville...it is such a beautiful area


Carbon? Over heated O2 sensor? I'm baffled now LOL

 

UPDATE -


Well, I finally got a hard code today. P0340 - Camshaft position sensor.


The van on my last drive started really hard. It has really doesn't do that and only once before about a month ago in which I wrote it off as it just being really humid and hot.


What is interesting is the van actually idles way better with the hard code on. I guess that sensor had been going for a while...I surprised it RUNS without that parts input :lol:


Sounds like the mystery is solved

 

Happen to know a part number or where to look for camshaft sensor. When I look on the part sites only get crankshaft sensor coming up.

 

rockauto sites like ebay call it a distributor pick up.


http://www.rockauto.com/catalog/more...nid=476&jpid=2

 

I installed a new pic up...the van is running good again. The idle is a lot better...it seems like this part had been going bad for awhile and just the stress of 11+ hour runs finally made it fail.