Contour Enthusiasts Group Archives Forums General Troubleshooting Miss under acceleration!

I am going crazy on this one! I still have a miss under low speed, high load acceleration!!!

I have replaced the coil pack (#2 went bad), replaced the plugs with Autolite Double Plats (gap was out to .062), and replaced the plug wires with Motorcrafts (#2 wire went bad). The old plugs were very white when I took them out. I cleaned the MAF sensor wire with Berryman's. I replaced every vacuum hose and tube that even appeared to be marginal. I double checked the PCV, and retightened the UIM to LIM. The only thing I havent done is replace the UIM to LIM gaskets.

I can't get rid of the off idle, full throttle miss. I also get an intermittent miss or buck when accelerating in OD at about 1800 to 2000 RPM at 1/2 to 3/4 throttle. I'm at my wits end! What should I do next? A car crusher comes to mind...

Try replacing the 3 plugs close to the firewall with Bosch +4's - if that works, do the rest - I posted a week or so back if you want further details.

I did much of what you've done and spent extra money for no reason when in the end I found it was the Autolites that were arcing down the outside of the ceramic and causing the misfire.

Let us know if that worked ...

wow.


I won't get in to this, but I will say:

RESEARCH THIS before you buy +4's... APP764 Autolite Double Platinums, or Motorcraft (PPM plugs, not FM) (they are identical to the autolites) are the only plugs you should use.. Of COURSE there are others (NGK, etc) but at three times the price, etc, autolites are THE recommended plug. (DOUBLE platinum..

Gap to 0.054

I know that the original poster already used the correct plugs (and wires!!!), so this does not help the PROBLEM, I thought that I should step in before someone ELSE reads this and buys the +4's.. GOOD LUCK TO YOU, sir, if you have any good results with the Bosch POS's.. (LONG TERM results.. ANY plug fires GREAT for a little while.)


Ray

I've searched the plug issue on this site pretty extensively previously and decided that the Motorcraft or Autolite double plats were the way to go. Not that there can't be a bad plug from anyone now and again...

But back on topic, I just wanted to add that the car isn't throwing any codes. I spoke with a friend who is a lead tech at the local stealership. He says that almost every time there is a miss or buck under acceleration, it is an MAF issue. I had put on a reman MAF from Advanced Auto Parts and I didn't see an improvement. I have to add, however, that when I did this, I later discovered that the #2 plug wire was bad so I replaced the plug wires and everything appeared to be O.K. I suppose that the plug wire could have been masking an MAF issue. I'm not sure and I don't have a definitive way to test the MAF. The problem has slowly crept back in and seems to be getting worse.

I will add that I found a couple of marginal and slightly cracked hoses in the vacuum system last night. Fixing them does seem to have improved throttle response a bit, but I still have the basic problem. Everything I've descirbed here has taken place over the last 6-8 weeks.

Any ideas on what to do next? Please !!!

Ray - I don't know where this thing all started about the +4's being bad but it seems things can sometimes blow out of proportion on these boards. Seems some people just reiterate what other so-called pundits on here have said without first-hand experience of their own and then next thing you know you've got a dozen people saying somrthing's bad when only 1 or 2 actually experienced it.

MY (and I repeat my) observations have been that the Autolites suck on my car .. period.

If I could get my camera to focus in close enough I'd post pics of the arcing lines on them. And this happened with stock wires, FMS wires, and Magnecores. I listened to the hype and changed everything except the Autolites (even tryed NEW Autolites) and spent a lot of money on things I didn't need to. And yes I even swapped a fellow SVT's MAF onto my car as well to no avail.

I'd like to ask the original poster to JUST try it. If it doesn't work for you then we'll know I'm wrong with your situation.

It took me over a year to find this problem so I'm just trying to help.

Where did you get your Coil Pack? I bought mine from Autozone (of all places ) and got a defective coil pack right off the shelf.

Also, you should check your firing order before starting to replace parts.

I had no CEL at anytime other than a flashing CEL for a couple of seconds ONCE when under load on the highway and passing.

Off idle at full throttle, it misses for about 1 second and then the thing runs like a striped-A**ed ape from about 1300 RPM right on up to red line. The other miss is only happens in the 1500-2200 RPM range when accelerating at just before the point where too-much throttle would make the tranny shift down (it's an ATX).

I changed the UIM to LIM gaskets last night and also cleaned the MAF with electonics cleaning solution, niether seems to have helped. What would be the next logical step?

By the way, the coilpack is a Sorenson from Advanced Auto Parts. When the old coil pack failed, the #2 cylinder simply went dead.

Identical symptoms to what I had when I mis-routed the plug wires. Please check the routing & keep in mind that they are not a direct correlation from coil pack to plug location - two of them are switched. I don't recall which off hand, but your original coil pack should have the numbers printed on it.