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Car "bucking" when accelerating

S

svthawk

New CEG'er
Joined
Mar 2, 2004
Messages
12
What kind of problem am I looking at?

Any gear I shift into, if i give more than about 10% throttle, the car will bounce and surge forward, as if I had missed the shift.

Manual svt contour with 120k miles.
 
Most probably fuel pump. Change the fuel filter first to see if it helps. Post check engine lights codes. What year?
 
Also, what RPM? Does it do this like, below 2500 and not as much when it's higher?

Low RPM bucking under load is classic misfire behavior.
 
Misfire

Misfire

Around 2200 RPM, moderate acceleration=new plugs/wires if original ones are still there OR carbon track on plug insulator (mine was plug #2, center rear bank.) Have to use Clean tools to install new plugs, to avoid misfire. I had misfire befor and after new plugs due to carbon track from dirt. If your car is newer 99-00 (returnless pump) and does it with 1/4 tank or less, pump issue.
 
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My car did a simular thing when it was under a half tank. I replaced the fuel pump and the problem went away.
 
this happened to me b4 but my problem was electrical. this was also right after i went turbocharged. The bucking would occur at full throttle when the turbo kicked in, right about 3500 rpm or so. It was more of a short hesitation and then blast off. Never actually figured out the problem as ma motor blew up a couple drives later. Anywayz, ur problem could be electrical also. when ma fuel pump went out, all it did was turn over n over. So it might not necessarily be that... from experience anyway.
 
I tried to clean the MAF, seemed to work for the weekend. car just started bucking againtoday, same conditions (more than tiny throttle). Also got P0300 and P0303 earlier when exiting a parking lot and trying to get to 30 to avoid getting hit. CEL was actuallly flashing.
 
PLUGS AND WIRES, for heaven's sake.

p0300 is for "random misfire" and p0303 is for misfire on cylinder 3.

ALSO - don't JUST do the new plugs, or JUST new wires - you need to replace them all. Bad wires will bake new plugs in a hurry; likewise bad plugs will cook your new wires.
 
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Autolite APP764's and Autolite wires. Set you back about $80. Get it done and quit doing senseless fixed.
 
I had the same problem (symptoms + P030x misfire codes/flashing CEL) and resisted doing plugs/wires since I had recently put new ones in (Ford racing wires + Autolite APP764). Apparently I had received bad wires or plugs because when I replaced them all with Autolite wires + APP764's the problem went away.

FYI the flashing CEL means misfire is occurring at that moment, so that's more of a reason to do the plugs/wires now.
 
SVT_CT said:
I had the same problem (symptoms + P030x misfire codes/flashing CEL) and resisted doing plugs/wires since I had recently put new ones in (Ford racing wires + Autolite APP764). Apparently I had received bad wires or plugs because when I replaced them all with Autolite wires + APP764's the problem went away.

FYI the flashing CEL means misfire is occurring at that moment, so that's more of a reason to do the plugs/wires now.
Click to expand...

There is a REALLY spotty record for Ford Racing wires over on NECO among Duratecs; that's what I was running when I had the misfire trouble as well, and I'm far from alone on that score.

Others have reported zero problems with the FR wires, but to me - the problem stories would be enough to persuade me to never use them again.
 
Yes, I have never had an issue with 2 sets but many have. I think AL's are the way to go since they are only $10 more. You can get them locally w/o waiting for shipping. They have a lifetime on them if you ever have an issue too. They feel and look like a better wire. You also don't ahve to grind the stock plastic holders.
 
2000 Contour SE, 4 cylinder, 99000 miles. This has been happening to my wife's car when she gets low on fuel. I figured it might be the fuel pump, but I was never certain until searching the forum. What fuel pump should I buy to replace it? These cars seem pretty picky as far as parts are concerned and was wondering if I should go with OEM from Ford or something I can get from Autozone/Advance Auto/etc?
 
1. For the Misfire: Check for carbon tracks on plugs (look like pencil marks or cracks on the ceramic insulator). Use a Clean sparkplug socket and silicone grease in the wire boots.

2. Fuel Pump: get it from teamfordparts or rockauto, stick with Motorcraft OEM. You may be able to clean the pickup sock, if budget tight, but because you have to bend metal (floor hole does not match) or drop tank, my opinion, put in a new one.
 
I got the new pump yesterday, and it's the re-designed part (vertical pump). The installation guide says there are tabs at the bottom of the tank that need to be cut off with a special tool. Is this true? Is there any way around it without having to get the special tool?
 
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