i have a 1996 Eldorado Touring Coupe.
i keep pulling up a random misfire code p0300.
i have changed the plugs,wires,fuel filter,airfilter and will not go away. for a while it was a on and off kinda thing. some days it would misfire somedays it wouldnt. ive tried all of the cheap repairs that i can think of i am a decent mechanic but i just dont have the equipment to fully diagnose this one any help would be greatly appreciated.

 

Are there any other codes? When do you feel misfire accel,cruise, idle...?

 

when in park or neutral it idles almost normal but you can feel the misfire. but when in drive or reverse it is terrible, so terrible that it sort of scares me to drive it. i have hardly any throttle response at low rpms. when at higher rpm it is not quite as bad though its still noticable. it also pulled up p0102 for the maf sensor but another mech told me that the misfire could be causing that code to show up. i dont really believe him but hey what do i know lol. i am leaning towards the ignition control module is bad or the coils are bad. i dont know for sure what it could be out of the two. my injectors may be bad or dirty also.

 

I am leaning towards a bad coil pack or two. When you changed the wires did you notice any corrosion or rust on any orthe coil posts? Do you see the rpm's fluxuate in park? more than 25, like 50 or more? You can always run a bottle of injector cleaner threw as well as MAF cleaner too.

 

MAF can cause many drivability concerns, include mifire. It tells the ecm how much air is going into the engine, its very important in regards to fuel control. Vacuum leak on engine side of sensor can cause code. If your disconnect sensor how done car run - Ecm will base fuel control off tp, coolant, and air temp sensors. If performance improves replace sensor. If you used re-useable oiled air filter over oiling will kill MAF.

 

i cleaned the maf sensor with some cleaner, when i changed the plugs and wires i did not notice any corrosion any where, i did run a bottle of seafoam through a full tank of premium fuel and yes when idling the rpms drop and raise non stop.

 

MAF code still present?

 

i dont have my own diagnostics computer so i dont know if the maf code came back on its own but i just tried unplugging the maf and im sure that would have set off the maf code but any how it didnt make it run any better so im leanin towards the coil packs/control module

 

im going to try pulling off the coil packs and checking their contacts and clean em up a bit

 

I had a similar problem with my 1995 STS...turned to be one of the 4 ignition coils that was failing.
Ron