moundhill

Here's the deal, I've been fighting a bad miss in my 99 for about 3 months now. We've been all over the place trying to fix it...
What it does is starts real hard and idles like it's gonna die. Going down the road it has no power and tugs and pulls..kinda like it's running out of gas. After a shift at low RPM's it feels like it's gonna die.
Here's a list of some of what we've done to try and fix it..

>Replaced all fuel injectors
>Replaced all plugs/wires
>New fuel rail
>Replaced almost all sensors
>Felt cat converter and it's not getting plugged
>Recently put a throttle body spacer and new intake on. So we took off the throttle body spacer, and tha fixed it temperarily, but now it's back to it's back to it's bad ways.
..I'm sure theres a little bit more. We did take over to Huddle Tire and have it looked at today and they put a tester on it and it said it's missing on all cylinders except for 3, and that my O2 Sensor behind my cat needs replaced. Also, it said something about a fuel injector Circuit. What's your guys' input here? What will fix this friggin miss?

It's a 99 with 199,000 miles on it.

Thanks fellers

EducatedCracker

Maybe clogged fuel filter or failing fuel pump.

77olds

My first guess would be the throttle position sensor. I hydrolocked a car of mine one time, and after draining the water and changing the oil and getting it running again, one day it started idling VERY erratically and would die sometimes. Changed the TPS and it was fine. You could try just replacing it and see what happens, or look up how to test it - that much, I do not know.

Those codes being thrown might just be the result of your problem, not the cause, so don't assume 100% that you need to start there.

moundhill

We changed the TPS already, and it ran good for ohh, about a day. Then Went to running bad again.

austinjoe13

How about a vacuum leak? Or MAP sensor? How's it run at higher RPMs?

tjwalker

*Post any code numbers. Even if there isn't a check engine light, I'd scan the computer to see if there are any pending codes. Codes are always invaluable in the troubleshooting process

*I don't see any fuel pressure readings here. It would be unwise not to verify this. Must be done with a gauge. For a 99, you should have 49 psi, plus or minus 5 psi.

*Where did you purchase your throttle position sensor? Not that unusual to get a faulty one out of the box from some of the big box parts stores.

*Map sensor can be tested with a meter and a manual. Be sure that the vacuum line leading to the MAP sensor is pulling good vacuum.

moundhill

Could POSSIBLY be a vaccuum leak but I doubt it. And we already changed the MAP.
At higher RPM's it runs OK, but still not where it should be power and fuel economy wise.

moundhill

I took it to one guy a while ago and he did a reading of the fuel pressure. It was fine, and the fuel injectors got changed since then. But it wouldnt hurt to get it tested again honestly.

77olds

I agree with tjwalker, it's VERY possible you bought a defective TPS. Return it and get another one. If you say it fixed the problem for a day then went back to running like crap... well, obviously the TPS made a difference, so that would lead me to believe it's possibly a defective one.

tjwalker

If you do replace this component, unless you got this TPS from the dealer, get your money back and buy the next one from the dealer. MOPAR engine management sensors are generally superior to aftermarket. I will pay the few extra bucks for both reliability AND longevity.

77olds

Yep. If you hold an aftermarket sensor up to an OEM sensor, you can see the difference in quality in everything from the plastic to the machining to the type of glue used.