I get an intermitent misfire code for the number 1 cylinder (Po301) on my 97 lhs. It seems to only happen when its hot outside and comes on after I fill up with gas usually. The car runs fine, its not sluggish, gets great mileage so can't figure out what would cause this.
We've been down this road with a 97 Dodge Ram (5.2L) and the road is bumpy. Ours was/is a P0307 (Cyl 7 misfire) and it has progressively gotten much worse over the last 13 months. Initialy we simply reset it and it was gone, well for a couple months anyway. Then it was back. Here's a list of things and repairs that HAVE NOT worked: Parts by the way are all Mopar New ignition coil New ignition wires New plugs new dist. cap flushing the injectors (multiple times) pouring in a can of combustion chamber cleaner (which fouled the plugs) replaced plugs again swapping #5 and #7 injectors (problem remains on #7) Applied TSB 18-48-98 (plug wire rerouting and addt'l insulation) Checked compression, all cyls 138~148 lbs Checked fuel pressure (52.8 psi) New Idle Air Control module (IAC) Disassemble & clean throttle body Chevron $$ gasoline (for last 1500 miles) Problem seems to occur at idle in gear and/or while decelerating from 20~30 mph down to a stop. According to a Chryco tech the P030x misfire codes are sometimes among the most difficult to isolate and clear. Just about anything can cause it, even when it is limited to occurring just on a single cylinder. Finding it is a crap shoot. Good luck.
if it's a 3.5 ltr look for a vaccum leak around the intake manifold, it's common when they get higher in mileage, 3.3s and 3.8;s were more common for ign coil packs etc
I'm not familiar with that particular car & engine. However, you could check out this article: https://www.obd-codes.com/p0300 I'm thinking the problem is most likely a bad spark plug or spark plug wire.