Where do I look now????

[laserx]

I had a problem with my engine. Every time I stopped in Drive or Park, the engine would shudder and the rpm's would drop by a couple of hundred then go back to normal. I went in and changed the PVC valve (not fun). Well, after doing this my "check engine" light came on. The code led me to the knock senor(s), went back in and saw that they were both cracked, so I changed both of them. The check engine light is now off. Here's my problem. On start up the original symtoms of rpm drop is still happening, but now after driving for afew minutes (maybe 5 minutes) the problem now goes away and it idles perfectly. Where do I look for the cold start shudder, problem fix? Since I'm not getting any message from the computer, I'm kind of stumped at to where to look or what to look for, to fix this one last problem (for now, anyway). Anyone got any idea's that would get me looking in the right direction, thanks in advance, regards dave

[CigarJohnny]

Not sure if it would pertain to the SVX but in my other cars, stuff like that would happen due to sudden drops in vacuum pressure. While RPM's were higher any leaks were not enough to effect sensors but once you let off the gas or suddenly dropped to idle the engine isn't making as much vacuum and odd things would happen with vacuum sensitive sensors until they compensated. Have you checked any hoses for cracks, dryrot and leaks? Vacuum hose is cheap and replacing them all might not be a bad idea anyway. I haven't had too much under the hood experience with my SVX but in all my other cars vacuum hoses lived and seemed to multiply like cockroaches in the engine compartment. Pinpointing leaks was a nightmare. I always just replaced them.

I'm sure someone else will be able to shoot my suggestion down if I'm wrong, but it wouldn't hurt to check. Anyone else?

[northernkanuck]

There was a previous discussion regarding gas companies changing the gas at this time of year to winter gas and this will cause problems with the SVX for a tankful or two until it adjusts. Is this an ongoing problem or just recent. This could be the cause if it is just recent. Give it a couple of tankfuls and see what happens.

Keith

[Beav]

To me it sounds as though the idle air controller is probably plugged up. Think of a car with a carb, in the morning when it was cold the engine needed the choke to operate properly. Part of that operation was to increase the idle speed. If that didn't happen the engine would be prone to stalling until it warmed up.

You'll need to remove the throttle body to get at it, but it sounds worse than it actually is. While you're in there you'll want to clean the throttle body as it's usually also nasty.

There was a previous discussion regarding gas companies changing the gas at this time of year to winter gas and this will cause problems with the SVX for a tankful or two until it adjusts. Is this an ongoing problem or just recent. This could be the cause if it is just recent. Give it a couple of tankfuls and see what happens. That reminds me, I need to change the summer air out of my tires and put winter air in.................

[Beav]

Originally posted by SVXCAPE
That reminds me, I need to change the summer air out of my tires and put winter air in.................

Just don't tick off the guy that does that for you. Some of 'em get mad and dump a glassfull of water inside each tire, creating a seasonally long out-of-balance condition in each tire, just for you mountain dwellers... Now how did I know about that??

[subymtnguy]

Well Beav, do you ever wish you where where you learned about that??

[laserx]

Finally, problem solved!!! Thank you everyone for trying to help me pin point the problem. The solution was to change the air flow sensor. What got me to take a look in this direction, was that my gas mileage was going down hill very fast. So I went to the dealer this morning and asked them if they would take off the one on a SVX they have on the lot and put it in mine to see if that would fix the problem. They did, and it did immediately fix the problem, just picked up the part (not cheap) and brought it home and popped it in, took all of 2 or 3 minutes, regards dave

[CigarJohnny]

Glad to hear you solved the problem! I will have to make a mental note of the solution in case it happens to mine