[enkeivette]

So, it's possible that I've posted this question before given my fantastic memory anyways, my moms car is having a bucking/ stumble issue.

WOT through the gears it's fine, but try to go from part throttle to WOT, and it lets off a half ass blow off from the BOV, and chokes out. Theres also a tad of an intake backfire. Any ideas?

[Shaolin Crane]

Ignition is my first thought, check the basics first.

[Vettezuki]

Ignition is one of course. Has it been driven regularly? If it's been sitting around a bunch bad gas can be all or a major contributing factor to things like this. My Vette is about 95% better and I attribute that heavily to burning through a shit gas. As you may recall it was bucking hard.

[enkeivette]

Car has always been driven regularly.

I guess I can order some new plug wires for it, I'm sure it's past due for new wires. But is there any reason a coil could cause this? Can a coil actually get weaker, or do they just fail.

Fuel seems more likely to me. Because first, as far as I know there is as much spark energy being exerted at 4k rpm whether you got there WOT through the rpm range, or whether you transitioned from part throttle to WOT. Second, an intake backfire is usually only caused by a lean condition or bad timing. Since its an comp controlled car, timing prob isn't an issue, which would point to a lean backfire... Backing up my fuel theory.

Only problem is this car doesn't have an inline fuel filter :/

[kdracer73]

What year is the car? Need to plug it into our trouble shooting network, and year will be needed. I know we have seen a lot of wire/coil issues with them. Some i've seen with carbon tracking down the side of spark plug and plug boot.


I've also seen 3 PT Cruisers with burnt exaust valves in the last year. Same motor?

[enkeivette]

It's an 03, I hooked up my lm2 and found no trouble codes... And we just had the plugs out when I pulled the head off a few months ago

[Shaolin Crane]

Originally Posted by enkeivette

Car has always been driven regularly.

I guess I can order some new plug wires for it, I'm sure it's past due for new wires. But is there any reason a coil could cause this? Can a coil actually get weaker, or do they just fail.

Fuel seems more likely to me. Because first, as far as I know there is as much spark energy being exerted at 4k rpm whether you got there WOT through the rpm range, or whether you transitioned from part throttle to WOT. Second, an intake backfire is usually only caused by a lean condition or bad timing. Since its an comp controlled car, timing prob isn't an issue, which would point to a lean backfire... Backing up my fuel theory.

Only problem is this car doesn't have an inline fuel filter :/

Intake backfire can also be a weak spark or inconsisten spark. When the alternator in my old f150 would start to go it would start backfiring through the intake cause voltage would drop and wala. Cough cough

[kdracer73]

Plugs , wires, and cam sensor are the most common issues.... for the symptom given.

[enkeivette]

Ok, I'm sold... I'll start with the easy stuff first.

[enkeivette]

And ya, same motor. But I just had the head off, valves looked fine. The PT cruisers tend to eat those motors up a lot more for some reason.

I'm guessing it has to do with the auto trans, added heat from poor ventilation, smaller intercooler, and the fact that PT owners are prob running organic shit oil because they don't know anything about the car.