Hard Start/Rough Idle. Guzzler

I own an 89' 98 with the Vin C 3800. For some reason its takes longer to start, idles hard in gear and seems to have a slight misfire. It also seems to be drinking gas as though it were free @ 11mpg. When it was extremely cold out I had to plug it in for 2 hours before it would start. Changed the plugs and wires, changed the PCV and had the fuel injectors cleaned. It starts much better but still seems to be hesitating after it has been sitting all night and idles rough when I am stopped at a light in gear, if I drop it into neutral it idles fine. The vehicle only has an alleged 75000mi (127000km). I get the occasional service engine soon light if I let it sit and idle to long but can not get it to show when I scan the ECM. I use to own an '87 98 and loved that car I would easily get 25-30mpg on it and that car had over 220,000km 133000mi. It met an unfortunate demise by blowing the timing belt on a start up.
With that being said I would really like to fix the small issues with this one as it as good of a 98 as you can get without being a Touring Sedan.
I am considering replacing the O2 sensor and the Fuel filter but have not gotten arround to that yet.
Any help would be appreciated Thanx

What engine did the 87 have that had a timing belt,just currious.

the 87 had the 3.8 engine not the 3800 engine. I may be wrong on the belt it may have been a chain on it my memory is a bit scetchy on that part I had it back in 2001. It was running real bad as i was driving it home that night and lack of knowledge on timming and firing issues led me to start it back up to take it to the mechanics. Well she backfired on start up and that was it RIP! Wish i had of fixed it though it was a real nice car.

yea, it sounds like you may have a timing problem. i just had to do this to my 87 Regency (its a chain on the 3.8L V6)

I just had this problem with my 87' Regency. It was running perfectly. whenti nto a store, came out. wouldnt start. we finally got it to start but it ran incredibly rough. got it home, did the same thing to me for about 2 weeks, had to drive a different vehicle. it finally completly died. it wouldnt fire correctly and only partially, you could hear a weak bang from each of the cylinders and smoke was coming out of the screws that hold the air filter in place. I did a tuneup on it, same thing. Auto_tech teacher thoguht it was teh fuel pump, i thought it made sense. so i got it towed to the shop. They found out it was the Timing chain, it had slip a couple teeth out something. a 500$ job, should have been about 800$ but my dad is the manager of an auto parts store and he knew the macanic so i got a nice break on the price. hopefully it something a lil cheaper then this but i would look into it.

Your problem is exactly what i experienced with my '87 as i was driving down the highway. You got lucky with yours, mine required a rebuild. The problem i encountered with the '89 98 I learned is that the 1 or more of the fuel injectors are leaking. The engine is flooding on start up and occasionally causes difficulty with initial firing. It is also the cause of the poor gas milleage as it is running rich.