I just replaced my front/rear valve cover gaskets along with my intake manifold gaskets. Over the past year, there has been a lot of dirty build up around the vavle covers and a darker color appearing around the ends of the intake manifold. Anyway, I replaced them all...problem solved....................

Well, I get everything installed and start the car up. (I had disconnected most of the wiring harness and hoses to get the intake manifold off...never done that before...what a pain!). Anyway, I hooked everything up. Car starts! RELIEF! I get in to go for a test trice....I wiggle the shifter ( 5 speed)...and the RPMs go up...I let go..they go down....I push it to the right...they go up..and let it go to middle..they go down? ....ok.... well, I check all my connectors from the wiring harness....one is loose...i pop it in..and no more RPM shifting! Alright! I drive out to wal mart....go over a speed bump...Check Engine Light! Noooooooo!

I check the codes and get a "EVAP canister purge control valve/solenoid valve"--(I think this was it)...and knock sensor (probably should have changed that while i had the manifold off....)

Well, Im not sure what each connector is...but I go checking again. The gray connector on top of the intake manifold near the throttle body had come loose. I popped it back in and reset the codes. Started up...no CEL!..wait...yup CEL came on again..this time the code was 0505...? no error! well, I try about 5 more times (resetting everytime) and always get 0505. Finally, I guess I finally did it right?...the CEL stays off (it didnt burn out cause it comes on at start up).

Well, car still feels a little weird...maybe cause I reset the ECU when I reset the codes? It did sit over night not connected to the battery.. Anyway, it gets better and right now(4 days later) feels pretty much like normal..and it getting really good gas mileage --- however, here is the reason for this post:

Let's say I'm going 50 mph for a few minutes, and I come across a red light. I take the car out of 5th and let it go to idle as I coast to the red light. Well, as it is descending to idle, it goes pretty far below the 500 rpm mark (which i can feel it doing) and then bounces back up and holds the idle fine...almost like it's having a hard time finding the idle position. It's fine after that. Maybe it's always done that and I just haven't noticed it? If I didn't hook something back up right i would think the car wouldnt run, CEL would be on, or Id be getting **** for mileage?

Any ideas?

 

im 5speed, mine does the same exact thing, when u throw it in neutral it drops to like 350-400 rpms then jumps back to normal. ive always thought it was normal cuz its done it forever, but i'll keep my eye on this thread for other thoughts.

 

Well, it might just be me "looking closely" at the car after the repair. Doesn't hurt to ask

--- cause I think I recall it doing it before...but Im just really noticing it now!

 

possible vacuum leak, tps off maybe(or dirtyTB), is idle correct?(just a thought i have an auto so???)

 

When you got it all back together, and the car didnt respond well, and i assume you were getting poor gas mileage because you state it got better, that was the knock sensor acting up. do a search and you will find out exactly why it responded the way it did: Safe Mode.
My 97 5SP does the same idle fluctuation and so did my 96 Auto. ive cleaned the IACV on both. considerably helped the 96, and havent tested the 97 because it is on jack stands waiting a new core support!
Clean the IACV and you should be good to go!

NM91

 

well I was going to clean out the IAVC...but I want to get the gasket from the dealer first. Anyway, I was looking around under the hood and heard/found the culprit. The hose from my CAI to the IACV had HUGE cracks in it. I also, checked the EGR guide tube and the bolts had come loose. I replaced the hose and tightened the bolts. Felt exactly like it did before I did the gasket replacement! ....except after pulling off the road and tightening the lug nuts that i forgot to tighten after doing a little brake work .....ha

 

lol i know what you mean. i did mine recently....uuummm, mine had trouble idiling too. but i was using old plugs that were in oil...i changed the gasket, cleaned the plugs, and stuck them back in....but after a while it started to misfire and had no power on the low rev band...also it was idiling really stupid, drops to 800rpm and jumps up and down for a while and then starts iddiling at 1300rpm..so i decided to change my plugs, bought NGK, unscrew my old ones and 2 of them are in oil...GAY....so i messed up on 2 of those round things, gotta rechange them. luckly in the front.....

so anyways, take out your plugs and check that they are good.


Paul