My Lebaron has been running great all through last year and this winter until recently it has been getting hard to start when warm. I would have to babysit the throttle and keep it from dying and it would just run really rough for 10 seconds or so. That problem has been getting progressively worse to where it is hard to start at all now, cold or warm. It smells like raw fuel when it does finally start and idles low and choppy. Also it has developed a miss under slight load. Under boost it makes great power, good AFR around 11.5 at WOT.
Put in new NGK BR9ES plugs this weekend. I was running Autolite 64's but I'm not sure if 64 is actually one heat range below the stock 65 so I wanted to change them anyway. I also gapped them at .28 instead of .35 thinking the coil might be getting weak. If anything it runs worse with the new plugs.
I had a code 21(O2) and 45(overboost), put in a new O2 sensor and coolant temp sensor last night. No codes popped up driving it around last night or after coming to work this morning. The overboosting was due to the w/g arm being too tight I fixed that awhile ago so it was just stored.
It did start a bit easier this morning but the miss was still present. Jay and I tested the fuel pressure and it is fine, I was thinking a bad FPR possibly but it looks good.
What else might be causing hard starts and missing like this? The car doesn't have AIS, I'm used to having to nurse the throttle a bit when it is cold but this is nothing like that. It just doesn't want to run at all.