Key on, engine off, fuel pump running, pressure must be 55psi to 61psi, so at 60psi, you're good there. 10 minutes after the pump shuts off, pressure must be above 50psi. 40psi after 30 minutes tells us there's no major leakdown. If the engine is running poorly, eventually the check engine light will come on and give you a trouble code. Post it, and we'll go from there.

 

"eventually"? It's been doing this since the end of July. lol

 

I don't know if it tells anything, but it seems to be much worse the first minute it two (open loop, closed loop, which is which I can never remember).

Exhaust smells bad. If this were a truck with a carburetor I'd say I had choke problems.

 

Cas, have you checked of any vacuum leaks? sorry, this thread is so long i may have missed it being adressed before

 

Vacuum leaks will cause a lean condition, not rich.

Maybe the check engine light bulb is burned out, or the indicating system has a problem... Does the check engine light come on and turn off with the bulb check? Have you checked for DTC's in memory? Keep in mind that your PCM does not have the capability to detect engine misfire, so it can't set a DTC or turn the light on for it.

When first started, the PCM operates in open loop. Depending on temperature, (ambient & coolant) it will switch to closed loop anywhere from a few seconds to a few minutes. During open loop, the PCM ignores the oxygen sensors and relies on inputs from the TPS, MAP, ECT, and IAT for fuel control. If there's a problem with one of them, the check engine light will come on.

 

I thought of that myself, but the check engine like does still light when I start it. I've been checking for codes once a day or more with nothing coming up.

I put 80-90 miles on it yesterday and today. No real change, no check engine light.

Gas milage wasn't good. That's what's funny because it/I've followed the exact same sequence of things as I did last year. Changed the pump, changed the FPR, (last year changed the spider after that) and following that it ran awful with terrible gas milage. But it threw the O2 sensor code, I changed it and it was great. This year oddly enough has followed the same exact pattern, only no code.


A question about sensors or whatever they are…. (being too lazy to find my book and look it up)

The unit on the top center of the plenum, what is it called and what does it do? When I unplug it, it seems to make no difference.

Same goes for the plug on top left of the air intake on the plenum (sort of opposite the TPS). When I unplug that it doesn't seem to matter either. (I just started unplugging things the other day to see what would happen… and nothing happened.

 

No real change after a couple weeks. Same deal with no power when starting from a dead stop. She revs up and starts to break up right where it needs it most to shift. Because of this it shifts late, or I have to let up to make it shift. If I don't it will sputter and backfire out the tail pipe.

A new thing I've noticed is when it's breaking up and sputtering, right at the end before it finally shifts I can hear it in my satellite radio, like an ignition noise.

Because of this I changed the coil yet again, but with no change in the problem. I have a new cap and rotor, only two months old (much better quality than the one before it, no change). New plugs, I changed them because it was time, not because I expected any change in the problem. My plug wires are a year, year and a half old. I don't know how old the distributor is, but its not original. Best guess would be 5-7 years old. I had the module go bad on me two years ago, I changed it and the pickup coil while I had it out.

My notion (hopes anyway) was that the coil might be breaking up under load and that's where the noise is coming from, but it seems that was wrong. I would think a bad plug wire would cause the noise all the time, not just at one point in a very limited range/load?
I suppose I can change them again, I'm throwing good money after bad.

I'm runnin out of time and options. I've been putting off the spider for last, but by the time I get to it I will have spent just as much as it would have cost on everything else. To me everything points to fuel, and was ready to bite bullet and buy spider number 3. But discovering this popping noise in the radio has given me pause.

 

So through replacement/removal, I know it's not the:

Fuel pump
Fuel filter
fuel pressure regulator
Throttle position sensor
Cat converter
O2 sensor
coil
cap/rotor
Plugs

So here I am faced with changing the spider again. May 2011 I put in a Standard products.
October 2012 I replaced it with an AC Delco. Sooo... what brand to try this year.

 

Well I did what I didn't want to do. Ordered another spider.

I put it in saturday and it ran great. For two days.

It's already started doing it again. Now I'm lost.

 

Figuring at this point, what the hell, and bought a group of junkyard parts off Ebay.

Changed the MAP sensor, ignition module and MTV… no change.


Thinking over my list of parts I remember two years ago when I changed the spider, I changed the plug that attaches to it as well. So it's not "new", but it's not original.