The car cranks and starts but instantly dies - won't hold and idle!

Will start and run with wide open throttle but will only reach 2000 RPM.

I can feather the throttle down to about 1000 RPM but below that it just dies.

Replaced fuel filter, cleaned mass air flow sensor, cleaned throttle body, disconnect batt to reset puter with no luck.

No codes and not in limp home mode.

I have a scan gauge and what is puzzling me is the timing, I can watch the timing go from 10 - 50 on the scan gauge which seems like a very wide range to me.

Would the car still run with a bad crank or cam sensor?

Any ideas?

Thanks in advance.

B

 

I could be wrong, but it sounds like the engine has a pretty good sized vacuum leak.
Usually start with the PCV valve and hose. They have a way of cracking ,going soft and opening up. It sounds like the engine is getting too much air and not enough fuel until the TPS tells the computer to increase the injector on time. Unmeasured air is possibly getting in and not being measured by the MAF sensor.Might pay to check it out.

 

Checke all vacuum lines and all seemed fine - even removed them and got suction from all of them.

The is 1 very small hose with nothing connected right by the TPS - it looks like nothing has ever been connected and no vacuum present on that line. Looks like a vent or something. Anyone have an idea?

I may remove the intake manifold and inspect for cracks.

You are correct that it sounds like too much air/not enough fuel.

Thanks for the suggestion.

B

 

Before you get involved in removing a lot of stuff, have you tried checking with a can of carburetor and choke cleaner and spraying around the intake manifold area and anyplace where there could be a vacuum leak. If the engine speed changes you will have found the area. Did you find and check that PCV hose?

 

UPDATE....

Car will start with wide open throttle and max out at 2000rpm.
Will not hold an idle.
NO CODES in computer!

100K miles

it died not 10 minutes after kid put $10 of cheap gas in it but it has been hard starting for 2-3 weeks now. Would crank, start and die. Would have to repeat this 2-3 times before car would stay running.

RR = Fuel Filter
RR = Both strainers inside fuel tank (pain in the butt)
RR = New, Clean, Good gas
Cleaned = Mass air flow sensor
Cleaned = Throttle Body (actually removed it and really cleaned it)
Checked = Intake and vacuum for leaks - none found
Checked = Exhaust - pushing out good pressure
Checked = Electrical connections and grounds - all appear good

With my Scan Gauge I watch the TPS with engine NOT running and i see 10 - 75 and throttle response is almost instant.
With engine running it max's out at 20 throttle response is very slow.

What is killing me is when the car died no check engine light and no codes.

When car is running at it's max RPM of 2000 it "Knock's" like timing is out of whack!

 

My 2007 Five Hundred had been running rough for a couple weeks with the Check Engine light on, and a misfire code for Cylinder #2. I had received the parts to fix the misfire (a new set of plugs and a new coil for #2) and I was planning to do the repair on the following weekend. Two days before the planned repair day, my wife reported the car had deteriorated rapidly to the conditions noted above. I completed the spark plug/coil swap, dreaming that all would be well. No such luck. My repair cleared the misfire code and the Check Engine light, and no other codes were present, but the emissions-related code checks scanned Incomplete and the car ran as before.

I took it to the dealer, who pronounced two of the three catalytic converters dead (clogged - the primary for the rear bank where Cylinder #2 resides, and the secondary under the car), and quoted me in excess of $3,000 for OEM replacements. That seemed a bit excessive, so a little online research led me to a pair of exact-fit aftermarket cats from RockAuto for a little over $300. The dealer was willing to install my parts and just charge me the same labor as before, around $300.

The moral of the story: if your car is misfiring - don't procrastinate, fix it ASAP. The catalytic converters won't tolerate all that excessive unburned fuel for very long. Mine went from fine to fouled in under 500 miles.