89 lincoln town car cutting out when warm

[GoodSamaritan]

Sorry to drop in with a request like this and then leave. We've been moving and our internet isn't up and running right yet.

At any rate a friend of mine with a very nice 89 Lincoln town car dropped by today with some issues.
The tps was bad, and the iac needed cleaning, and both of those were taken care of before going further.

Now the car idles smooth as silk, but after about 10 minutes on the road, it starts losing power at part throttle. There is a noticeable crackling in the exhaust as if unburned fuel is making it that far before getting enough heat/air to detonate.
There is no pinging from the engine, and the timing is good.

It has a new distributor in it, with a new ign module. They had already replaced the coil as well.
It has new (proper) plugs, and the plug wires are good.

I am beginning to suspect either the map sensor or one of the O2 sensors in going intermittent on it.

Any ideas mangs?

[Pirate]

Some possibilities.....

1. Cats are dying. Not the feline kind, of course, but if he's had some issues with other EFI components, and has driven the car a while while it's been running lean due to incorrect TPS signal....the cats may have been damaged, and are backing up during a drive.

2. Check fuel pressure as soon as possible after the rough running commences....or if possible, drive along with a fuel pressure gauge (if you have one with a long-enough hose). The pump may be on its last legs.....

3. There's a possibility with one of the O2 sensors....check to see if codes have been thrown.

[gadget73]

What he said. MAP sensors usually aren't a problem, and when I've seen or heard of one failing, it didn't fail in that particular manner. Not saying its impossible, but its not where I'd be starting.

Dumb question but the fuel filter has been replaced this millenium right?

[GoodSamaritan]

Fuel pump is less than a year old, and the filter was replaced at that time.

I don't have the car here at the moment, but I will take another crack at it this weekend though.

I haven't checked the fuel pressure because I haven't been able to find my @#$%% gauge. I'm beginning to wonder if it got stolen along with a bunch of my other stuff when my evil uncle decided to walk off with everything in sight... At any rate, are you suggesting low fuel pressure, or too high due to a bad regulator?



Pirate, I always thought that once a cat goes bad, it is stopped up for good. Are you saying the problem gets worse as the car warms up? Before it warms up, it moves out pretty good for a town car with 3.08's under it.