Hard Starting then Muffled Back Fire...

[UTEP]

Howdy,

2000 4R Ltd 4x4 203K miles.

Brand new battery with extra CCA's so it's not the battery.

Engine turns strong but doesn't want to catch. A little gas and it fires up with a little burp.

Been doing a lot of long hauls but did a real good tune up/cleaning in November. About 20K from indicated timing belt change.

No CEL. Runs fine but I can kinda feel a stumble at speed sometimes. Almost like a strong cross wind (in fact may be a cross wind/dust devil as it is very inconsistent)

Should I go with a Seafoam clean and go back through the intake?

Any other ideas?

Thanks,

UetP

 

[Insmonia9335]

Possible timing issue, sounds like you're misfiring cylinders, but if your check engine light isn't coming on, then it's not something being sensed (or your bulb is out) But before we dive that far, I'd check your fuel filter. Sometimes if that thing is clogged up it'll have issues getting fuel in and out of your injectors. A backfire is caused by and overinjection of fuel into your cylinder head and then an sudden ignition, and the fuel system leading to the tank is intended to be a vacuum. If it was me, that would be the first thing I would check.

 

[Insmonia9335]

Mine did this when my fuel filter needed to be changed, and I didn't find that out until my fuel pump gave out. It would do the same thing on startup, a sputter, burp, then run strong. After acceleration it would stumble.

 

[Insmonia9335]

I personally wouldn't think it has to do with your intake. Some people swear by seafoam, and I've personally never used it, I don't think it does all that much. Check your fuel filter, then your spark plugs. Make sure they're all fully connected, and that none of your wires are loose there. You might just have a loose wire or a short too, but start with that fuel filter. It's trying to suck gas, not getting any, stumbling, then getting an excess, and then firing hard (thus the backfire)

 

[UTEP]

Thanks,

Fuel filter huh....

I have about 30K on mine. Thought they were good for longer than that but guess one tank of sludgy fuel would take care of that.

I'll check wires too.

Thanks,

U

 

[soupkitchen]

sounds timing related to me too with the backfiring...maybe pull the top cover and make sure belt and gears look good. Possibly bad coolant temp sensor if that all looks good??

check for vacuum leaks too.

 

[Doc2012]

throttle position sensor.

 

[Insmonia9335]

Thanks,

Fuel filter huh....

I have about 30K on mine. Thought they were good for longer than that but guess one tank of sludgy fuel would take care of that.

I'll check wires too.

Thanks,

U

Also, my dad is a bit of a car wiz, and upon consulting him, he said check your vacuum system. If you've got a vacuum leak it will do the same thing. Check all hoses in the EGR system, making sure none of them are cracked or have leaks. Here's a diagram of what I'm talking about.