2001 T&C 3.8l hesitation/misfire no codes showing initially - SOLVED! Thank you all.
Hello, this is my first time posting to the forum but I have benefited more times I can count from the information available here and for that I am grateful.
This was my situation. I have a 2001 Chrysler T&C LXi 3.8l ohv. with 160000 mi. Just the body style alone creates confusion for some parts suppliers as some think that the Lxi was only available with 3.3l. Any way, for about 6 mos the vehicle had been experiencing hesitation and misfire during acceleration. I could peg the throttle in P and everything seems fine but put it under load and I cannot get the tac over 2000 as it misses, hesitates and loses power. while driving, sometimes I could get good acceleration with just a little bit of hesitation and no misses, but mostly it would hesitate/misfire at some point. Idled fine with the exception of a hiccup every 5 seconds. I took it on the highway and pushed through the misfires and finally got the cel to flash, up to this point there were no codes except for a small evap leak several months ago which I remedied by replacing the purge vent(TSB).The code was a misfire in cylinder 2 so I now had somewhere to start looking. I replaced plugs and wires when this First started occurring with no change. My gut feeling was fuel injectors so I ran some techron in the tank and it actually seemed to help some but the miss was still there. I checked the fuel pressure and it was within specs. So I pulled the intake and checked the wiring harness as these are known to become damaged by heat and chaffing. There were a couple of wires that had small bare spots but were not contacting each other, or grounding to rail/intake. I have no clue how they deteriorated in just a couple of random spots inside the heat jacket. I cleaned a small amount of corrosion and wrapped them up good. Also notice number 2 injector had a crack in the housing. I don't know if this could cause leak but it seemed too much of a coincidence. I ordered a set of injectors, which btw increased in price from $18.99 to $69.99 overnight, literally. Finally got remans for $18 ea.on ebay. inspecting fuel rail, noticed some varnish buildup on fuel rail ports and cleaned it thoroughly. This being the 5th time I had the intake off in the last month, I was able to complete the entire job in 45min, cleaning fuel rail took a while to remove varnish. After installing new injectors, even though I had much better throttle response I still had the miss, every 5 seconds, like fuel is dribbling out of an injector. I disconnect fuel pump relay and coil, pull the #2 plug, stick my finger in the hole and have someone crank engine and my finger is quickly pushed out of the hole forcefully. Now I know that this is far from an accurate test for compression but I do not have a compression tester. Next I held a piece of paper over the tailpipe with engine running and got a constant push, no fluttering. Again, not exactly conclusive but, no leak down tester so I do what I can. Feeling moderately confident this was not a compression or valve issue, I move on to coil. Pull it out, Check resistance across posts, ok. check voltage at contacts, again ok. I had already Checked spark on all cylinders(with the proper tool) but did not test spark under load. At some point, I was checking my ignition wire resistance and left one wire unplugged(no. 2 of course). Started the vehicle later and noticed it was running a little rough as I drove away, there was a significant loss of power, felt like a cylinder was not firing at all so I pull over open hood and see the wire. I reconnect but there is no spark. I pull it, holding it close to plug and nothing. I pull next wire and see strong spark, swap wires, still nothing on no.2. I figure driving a few minutes with the wire unplugged could have possibly pushed a failing coil over the edge so I replaced the coil today. Response is fast and acceleration is smooth with no hesitation or misfire and no missing at idle either. I do notice a slight rumble or vibration as transmission shifts from 1st to 2nd but that is probably just my transmission going bad
Question: Why can't I get the engine to tach over 2000rpm with foot on brake in gear? It doesn't hesitate or skip like before, it just won't go higher than 2000rpm. Driving down the road it drives/accelerates great, better than it has for a long time. No hesitation or misfire- should I be concerned?
I was gearing up to replace crank sensor after reading case study with same symptoms, for $20 part it seemed reasonable but I could not find the darned thing on the bell housing where it is supposedly located. At this point I am glad I did not try to replace it. I have read they can become fused to the port they are in and often the plastic breaks and it becomes a real pita to get it out.
Anyhow, I was sure this was an injector or wiring harness issue but turns out it was a weak coil that was failing under load to 1 or maybe 2 cylinders. For all I know Cyl 5 was also missing but not enough to throw code. So aside from the slight transmission vibration and the RPM thing, all is well with my van. I hope by sharing my experience I can help someone else who may be having similar issues. I want to thank you all for your contributions as they have helped me many times.