2000 ssei "Shudders" at idle, Stumbles on accelera
 

Car "shudders" when idle in park...smoothes out when put in gear. Also sometimes "stummbles, hesitates" on acceleration. Had #4 misfire code that showed up at dealer.Dealer cleaned fuel injectors, replaced fuel filter. Put on new spark plugs and wires. Has clean air filter and runs like a scalded ape otherwise. Have seen lots of peeps describe same trouble and recommended to check fuel pressure. Is fuel pump high failure item? Oh yea...86K miles on car.

Any input appreciated.

It wouldn't hurt to check fuel pressure on the rail, but I'm not sure if that is your problem. Didn't the dealership techs check that? There's also the Fuel Pressure Regulator (FPR) that could be a potential problem assuming everything on the ignition side is in order.

Mark I agree....let's add...

Double check plug wires 4 and 6. Ensure neither are too close or laying on the O2 sensor.

Been there..seen this. ;) Easy to check and correct if it's the issue.

Do you 'have' or 'had' the misfire code? In other words did the work the dealer do get rid of the code?

Thanks for the feedback guys....

MarkWB---Fuel pressure regulator, not a bad thought at all. Gonna have to check that one.

Billboost37---I replaced the wires and plugs after the car came back from dealer. Ran wires exactly as factory wires were run, and have just double checked, not laying on O2 sensor. Another good idea though!

TechnicalTed---The code showed for the dealer during their code scan but nothing showed for me on the DIC(driver information center).

This is a pretty intermittent problem and does not happen all of the time,but, has been becoming more frequent now. I watched yesterday as I was driving noticed that the Tach does not fluctuate with the hesitations. That kinda makes me think...look at transmision,motor mounts, driveline and not engine. Does that sound reasonable or am I all wet????

What size is that blasted supercharger oil fill plug?

Cleaned throttle body and fixed a cracked vaccum hose. Car running pretty good now. Still has poor idle at times but much better now.

Looks like dirty throttle bodies are faairly common and definately a source of poor performance.