Surging Idle and misfire

[rrhayden]

Thanks for looking !!
The situation is this, my 92 LT! will surge at idle increasing in rpm by 2oo to 400. When this happens the car will studder when under a load, like driving at 40 and pressing the peddle quickly. Now the od part, it only happens on hot days when the engine temp is over 200. If it is a cool day and the engine temp is 200, it runs good. I have chenged the o2 sensors, any other thoughts

Thanks
Ron

 

[hAZcAT]

join the club this sounds like my problem exactly. at 2k rpms in 85-90 weather it is still the beast that we all have come to love. I cleaned the MAF and found bugs in the little screen that protects the maf, how they got to there pass the air filter, I will never know. on friday I am changeing all of the o2 sensors , but I won't know for a long time if any changes as weather here on the coast is normaly in the 60s. I am been reading allot and I am begining to look at the EGR and I am going to change out the spark plugs, but I don't belive new plugs will help. good luck please tell me what you find thanks.....

 

[rrhayden]

Thanks for the reply, I will deffinatly post the solution once I get it worked out. Best of luck to you , let me know what you find also.


Ron

 

[hAZcAT]

I just put some (2 bottles) of tht stp fuel stuff in the gas and took the car out it helped with the take off stumble. I am begining to wonder if the at the gas station the wrong fuel was put in, (in Oregon they fill your tank, a bit of service).

 

[WhalePirot]

Can you pull any codes? Hard or soft ones? No SES light?

 

[hAZcAT]

no ses light and now the car seems to run fine, I hate not haveing a "hard fix"

 

[SSTibet]

Take your car to an authorized dealer or a good mechanic, get it hooked up to the diagnostics computer and let him / her check the car in all aspects. That's how I found my O2 sensors were bad. Guess work usually takes more time, money and frustration. I have also changed my fuel station and added injector cleaner. Running like a butterfly now.

hey maybe it is the IAT sensor (intake air temperature), but again this is all guess work... Go for a good test.