1999 e430 mecerdes rough idel and missfires cyl 1 3 4

SOURCE: benz e420 multiple cyl missfire

also check and see if the updated Mass Air Flow sensor has been installed, these go bad all the time causing all kinds of weird misfires and other problems.

SOURCE: cylinder 5 missfire 1999 tahoe

How is the pressure in the fuel rail? a low pressure will cause erratic firing of the injectors - the further down the rail u get usually the worse the problem. If the fuel filter was not changed regularly or if the vehicle stood for a while, dirty fuel/standing fuel at some time in the recent past, this **** will accumulate in tyhe injectors. To avoid spending a loada cash, swap a few injectors around and see if the problem moves with the injector.

SOURCE: 2000chevy blazer random cyl missfire number 1 cyl

Just to let you Know what you R getting into-I just got rid of My 2000 Blazer (THANK GOD)!!!! If you check out the Recalls and Complaints Online for the 2000 and Up Chevy Blazer you will be Reading for Months!!!! I am Chevy to the BONE and bought this for My Wife-It was GREAT for the first 15000 Miles and then Everything went Haywire! The Seats Broke, Lights quit, Tranny went Twice, Brakes Failed 3 Times, NEVER Ran Right again, Guages quit working, ON and ON and ON. GM will NOT honor these Recalls and Fixing them is REALLY Expensive. Just MY Opinion But, GET RID OF IT WHILE YOU CAN!!!! Took a BIG loss on Mine and Don't Regret it!!!!

Ned C Cook

• 3433 Answers
• Posted on Nov 07, 2009

SOURCE: 1999 Denali rough idel and driving

You should have 2 02 sensors in your exhaust system. The second one trips the ligt if your emmissions are too high abd it monitors the condition and efficiency of the cat converter. The 02 sensor in front of the muffler monitors the fuel adjustment for too rich or too lean. Now, on a cold start there ias a "cold start valve tha enriches your fuel like a choke. It can be the culprit because the #2 02 sensor is doing its job. The cold start valve can be chk'd to see if it is working by observing it.. It is behind the Throttle body. It should be clicking. Good luck and I hope this helped. Oh, wwhen the engine warms up, and you have clear the exhaust of excess fuel the light should go out.

SOURCE: Hi all, my 99 sub.350,300k,missfire #2

Have you checked the distr cap for cracks??

If plug is oily looking on brand new plug I would suspect worn rings, which would also explain the high PSI. (Motor job in the wind) Especially for 300K.