stanz

iTrader: (1)

Just completed an 850 mile road trip this weekend with multiple off road stints. Everything was going seemingly fine.

But two issues, crept up:

1) First early in the trip I noticed after the motor was warm and had been running at highway speed for a while, I would develop this issue at idle once I slowed down: it would continuously cycle in climbing up to about 1,100-1,200 rpm and then drop back down to my normal 850-900rpm setting.

I assumed that this was caused by the IAC valve acting up and deemed it manageable for the time being (I was in very remote central/eastern oregon -- tiny towns, no cell signal for sometimes over 100 miles).

I didn't want to cut the trip so I kept going -- didn't seem to get any worse.

2) Everything else was going fine up until mid-day yesterday, I had now covered over 600 miles highway and off-road. I stopped in a tiny town and got gas and then decided to go visit a ghost town I had read about... 'only access was via a 17 mile gravel mountain road'... that's when things started acting up... when I'm 4 miles away from one of the more remote spots in Oregon...

At first, I'm cruising down a slight grade giving it steady throttle in 3rd gear and bam... it feels like someone just rear ended me -- the rpms are at steady 2800 and didn't flicker. I found that odd, but thought maybe it was the road.

Just as I complete mile 17 into the ghost town, I feel bam bam bam... each time I loose power for a moment, but the rpms are not dipping. I pull over, the idle is doing that circuit up and down again... nothing better or worse, I then try to move... 1 st gear, shift at around 2k - no prob, 2nd gear shift climbs to 2500 and bam again.

I pulled over popped the hood. Everything looks as it should but I noticed the lead wires for the coil that run over the valve cover are laying on the spark plug wires. I thought maybe I'm getting some cross- communication. I zip tie the wire up out of place, let it sit for a few minutes to cool down, start it up and it drives great for about 2 hours -- no more issues.

I regain some confidence and continue. I'm now in another tiny town (everything closed on Sunday), cruising through at 35mph and bam... there it is again... over and over. I notice that if I keep it at a very gentle throttle the bucking is less frequent, but if I open it up to 1/4 or more it seems to get worse, but still the rpms never flutter even for a second.

I don't have many options but to crawl through crazy treacherous mountain passes for the next 90 miles -- not exceeding 35mph -- it took a while. And then all of a sudden it went away just like that. I was about to go about another 60+ miles with no issue -- I made up for some lost time and was cruising along at 75mph running through all the gears and the full rpm guage.

The last 50 miles were brutal. It came back with a vengeance for a spurt and then went away again.

If it was an automatic I would have guessed it was the tranny failing. It felt like axle wrap every time it bucked.

Here's what I know:
-CEL never went on
-Temp gauge never rose beyond normal
-RPMs never fluttered for a moment during any of this
-Seemed to react to throttle position
-The bucking started less than 30 mins after getting gas in the small town
-I added a bottle of fuel injector cleaner at my next fill up and continued to top off the tank every chance I had to try to dilute any possible bad gas
-Fuel filter is only three years old
-Clutch age is unknown
-Full exhaust, header to tailpipe is about a year old - doubt it's a clogged cat
-New denso O2 sesnor about a year old

My thoughts:
-Assuming the IAC is to blame for the climbing/falling rpm and not related to the bucking -- would be nice if it was the cure for all
-Perhaps this is TPS, EGR or MAF related?
-Could it even be the clutch slipping? It's 5spd
-Thinking spark and fuel are not possibilities since the rpm never fluttered

Thoughts?