Hey guys, figured I'd post here as I'm trying to get to a scanner but my loaded trailer and really awful running truck isn't helping matters. I'm on my phone so I'll keep it short, 96 3/4 ton 2wd, new plenum, cap, rotor, wires plugs cam position sensor both 02s, new cat with duals, now my check engine light is on, intermittently flashing and when it flashes I am missing and losing all power. Checked coil with my multimeter and resitance came in within books specs. Any ideas? Thanks. Stranded in Jersey...

 

check oil ...a flashing engine light isnt good ,if it was steady light it would be something minor so you may noy want it running too u find the problem

 

did you change the plenum with another gasket? or did you get the reienforcment kit?

 

CEL p301-308 indicates a misfire, and flashing CEL indicates misfire in-progress. could be any of a long list including burned plug wire laying on manifold, cracked plug wire, loose plug wire, plug wires touching and misfiring, crack dist cap, loose dist cap, fouled plug, crank position sensor, cam position sensor, vac leak, fuel deliver problem, all the way to catastrophic problem of cracked head.

 

A coil can cause a misfire by breaking down under load even if it passes a resistance test. And a fairly inexpensive guess.

 

Really? About the coil? Cause I was maybe thinking that.

All in all what a freaking two days here. I left bright and early yesterday morning to get a hot tub (medium pimpin' with a used hot tub for $100 in excellent shape) and on the way back from getting it (out by PA) this thing started howlin' it's problems.

Well, I had the cap and rotor, put that on, nothing. Then I borrowed a car late last nite to get home and early this morning went back with tools. I couldnt check the cam pos. sensor by myself (without either laser vision or 4 more hands given the STUPID placement of the dizzy) so I just bought one and the next trip bought a nice cheapo scanner. Put it in, nothing. Cleared the codes and all the sudden ran like a dream, like ran SO much better than it ever did before. Finally didnt smell of gas anymore, thought I was home safe. Hooked up my trailer and it started again as soon as I hit the highway. Before getting the trailer back on it I took it out for a harsh 10 mile ride, and it didn't so much as skip a beat. I was winding 2nd out, really giving it the business. But as soon as the trailer was on, it was an unstable pup.

Went down the Parkway (one of our major highways, that if you break down on they really $tick it to you, and way worse if you have a trailer) so I decided to back road it. Well, given the circumstances I had to put the dizzy back together I guess I missed a screw (out of two) and it came apart. No biggie, fixed it up in a Church, and it was one of those wierdo "who goes here" type churches. People were dressed wierd, needless to say I worked quick. Got it running, hit the highway and it died. Upon inspection on yet another unplanned trip, the metal tang on the rotor popped off. Yay China!

So luckily I had the old one, and put that back in, hobbled it home. Really hobbled it.

So, on the brightside every so often I would stop and read/clear the codes. Now Im just getting all the P0300s and a 171 for lean. So, Im wondering if my pump could be weakening?

This was an adventure, Im beat as can be, and I'm not going any further with the investigation tonight. Thanks for posting guys! I'll let ya know what happened. This truck has been a downright nightmare so far, but I've got too much time into it to get rid of it and the duals I just put on sound nice, so here I am haha.

 

glad you made it home. working on the side of the road sucks.
since it runs a lot better after resetting the pcm, and then it "learns" to run like $hit, then it might be a sensor feeding bad data.

you mentioned recent muffler work. that makes me suspect 02's are damaged. generally the front one has a lot more influence. i always thought it did all the tuning work, although some people report otherwise.

the 171 lean can come from vac leak, plenum leak, and/or fuel delivery. you can check fuel pressure with a gauge, should be about 49 psi, however, this won't identify a plugged up or faulty injector. if you ever get a consistent p30x, you can move the injector to see if the problem moves with it.

if nothing obvious shows up, you might be better off to pay someone for an hour of diagnostic time with a real time scanner to figure out whats wrong rather than guessing, although i'm guilty of replacing sensors and keeping a set of spares...

 

Ha, I'm the same way. See the thing with this truck was I got a good deal on it, but the previous owner kept it meticulously clean yet out of the shop always. No maintenance, I think he bought new trucks when the old ones got fed up of the neglect.

I really, really hope this isn't an 02 as I just replaced them not even 3 mos ago.

It seems every step I take gets it further to perfect, and now it doesn't smell like gas anymore, it seemed to be running rich a lot. So, ignition is firing nice and hot, that's all gone.

Now I have to unload my trailer at some point today, Im going to clean the truck out (friggin cat litter spilled in it, what a mess) and I might reset it and take it out. It really doesn't seem to have any issues when not being put under load, so my next step as you mentioned is I think I'll pick up a fuel pressure gauge, I have a hunch that the pump is getting weak or something is blocking fuel. I mean yeah vacuum leak or plenum w/ a leak will leak, this thing runs like a top then all the sudden it doesnt, there is no in between, so I doubt its a vacuum leak.

Let's see what we come up with. If nothing else the hot tub I picked up is home, so if the Dodge really kicks my butt, a little water fill and a 220v line and I'll forget all about it!

 

$100 damn.....I paid 45 times that for mine when it was new.....sigh!....dont forget the ground fault breaker within ten feet of the tub...

 

Alrite well it's going to be, eventually at some point today, sunny and warm in NJ. Im going to take a better look. It's just become a dump in the bed and a shelf inside for the week. I did get a chance yesterday to get a cheapo fuel pressure gauge and hook it up. I cut it in half, extended the fuel pressure gauge so I could drive the truck and monitor the pressure, all good except I didn't hit the safety latch like I thought I did and the hood flew open. I kept it slow incase this happened, and did it on our country backroads here as a precaution, so no harm, no foul.

Anywho, got it to stumble and run like ****, fuel pressure was around 50, didn't budge, even when the problem showed itself.

Now, at idle, it will throw a P0171 even though the CEL doesn't come on. When driving the CEL comes on in no time, and throws 171/172. I didn't (yesterday) get any P0300s, but couldn't get em to stop last wk, clearing the codes every few minutes, and it would be pretty consistently ALL the cylinders, not just specific.

I'm kind of leaning toward getting a crank position sensor for this, or cleaning it out. I cant get in there to test it like the shop manual says, and Ive replaced mostly everything on this turd. Including both 02s, plenum, wires, plugs, cam sensor, cap/rotor, yadi yadi.

I was really thinking the fuel pressure would die when the truck did, I'm surprised that it didnt, but after all this, I'm kind of getting the feeling this truck will never be "fixed". I've met my match.