"pop" and hesitation at startup
 

Hey everyone. I've never had a start up/warm-up problem with my 93 5.0 (166K..still kicks!)..until this past week.
After startup, the car hesitates on the street and I usually here a "pop" or two coming from underneath the hood. This only happens during startup. After a few minutes, it goes back to normal w/o a problem. Iwas wondering if it's any of the following:
1. Bad 02 sensors
2. EGR valve sticking or defective
3. Vacuum leak.
4. Bad distr. cap
I cleaned the heck out of the throttle body and I pretty much have new plugs and wires.
Need some help. Thanks!
fongo

Here's what you do, check for vacuum leakes, tune it up, clean your egr, and what is the most important is check you Air temp sensor on the intake manifold. If its bad it will pop. pop is from a lean condition. check your injectors and get them cleaned if nessecary.

Could also be a MAF or ECT sensor, but testing would be recommended....no wait, 166k miles? If they're still the original parts, I'd change everything I could afford but especially those two since they have the largest effect on a/f ratio.

But yeah, you're on the right track. Could also be leaning out due to inadequate fuel pressure. Test the fuel pressure to be sure. My '87 did the same thing right before the fuel pump took a dump. :(

With that kind of mileage i bet its time for new injectors. And definetly new Vacuum lines. if you haven't changed your 02 sensors do so, and the mass air sensor could be dirty and going bad.. Again also have the TFI module tested.. If thats the original, Please change that.. Its worthless and for sure gunna leave you stranded soon.

thanks fellas. After considering the topic along with other fellow car enthusiasts, I'm starting out by replacing the engine cooling thermosensor ECT and the air charge thermosensor ACT. I had new 02 sensors, my MAF appears fine.
God forbig its the TFI..I'm in deep doo-doo if that's the case!
Ciao...

if its the TFI its a cheap fix, 39 bucks max for the unit... Don't sweat it..

I had the same problem on my 84 carbed motor, I changed the intake maifold gaskets, (oil leak from lifter valley), and I didnt re torque the manifold after a couple of heat cycles, sure enough, I had the same probs.