[James Scott]

I've had this cold startup problem intermittently for over a year. Recently (after very little problems in the summer) the problem started to come back, but then went away! The only things I've done recently are: 1) add a couple of different oil additives (Rislone most recently after another brand) to treat sticky lifters/valves to help with my startup ticking problem and 2) Several fuel treatments in tankfuls of gas (Techron first, then Berryman's) and 3) Octane booster tankfuls (in about 3 tankfuls of gas). Even tho we've had cold weather for us here, I've had no rough idle for almost 2 months!!!

I've been on a thread about a higher fuel pressure fpr for our SVX's. See "Fuel Pressure" under Tech Q & A. This fpr will help at warmup and WOT to increase fuel delivery to help with a stock lean condition. I wonder if I haven't increased this lean condition at warmup by putting in a drop-in K&N air filter which increases airflow (AND thereby increases the lean condition at warmup and WOT)? [I will be installing the fpr soon!] I'm wondering how many of you have mods that increase airflow which could exacerbate the stock lean condition at wot and WARMUP!?

I don't suggest replacing the injector you think you've located by pulling the injector harnesses when idling rough! I did the same thing, thought I located the cylinder (injector or coilpack), replaced both injector and coil on suspect cylinder with no change ($200)! Later, while pulling injector connectors during another rough idle period, I located A DIFFERENT CYLINDER INDICATING NO CHANGE WHEN INJECTOR CONNECTOR WAS REMOVED AT ROUGH IDLE! Oh well!

If you search under "rough idle" you can see some of the many things I did to try and cure this problem over the last year (my high speed shuddering turned out to be the same malady at high speed. I stopped during the high speed shuddering rather suddenly [in the country] to find the same rough idle!).

I'll let you know if I glean any more wisdom about this syndrome. Please keep at it. Although my problem is gone for now, I can't be confident it's solved (since there was no clear cause and effect identified)! I thought it was going to be the MAF, but that swap proved to be fruitless. KEEP LOOKING UP! THANKS!

P.S. I've also been using the better gas stations here lately at someones suggestion (Chevron, 76, Shell), avoiding especially the independent stations (one of which I had been using almost exclusively)???