no acceleration 1985 fltwd brougham

[bishop1]

Please help!! my 1985 fleetwood brougham is acting up and it is completely strange. The car doesn't shudder and idles fine so I don't think it is a spark or electrical problem, it runs fine for the first 6m or so and then when I put the car under load or step on the gas it goes about 10mph max! without a shudder it just feels like the car is in neutral but goes about 10 the tranny is fine, it is completely strange I replaced some vacuum lines and cap and rotor, new plugs,etc. if any one has advice I'd be most gracious

[Cadillac Giovanni]

Check the exhaust system for a blockage, especially the catalytic converter. I would also try not to drive, it because if you force it it can cause severe damage to the engine.

After that, I'm not sure... I'll have to think about it.

[Old Fleetwood]

If I understand what you describe - you drive for a while and then when you mash it the car slows - then I can only tell you what happened to me:
I had a full size Ford (company car) that did exactly the same thing and it did it on an interstate highway without any warning.
Cut to the chase:
I nursed it to a dealer who found that a baffle in the muffler had been flapping around and closed over the outlet when exhaust pressure increased. Totally weird, but it happened and Ford replaced the muffler at no charge (car had 45,000 miles on it) and sent the muffler back to the factory.
I have no idea if that's your problem, but that's what happened to me.

[H9C2]

Being not at all familiar with automatic transmissions, I would say if the engine revs but the car does not accelerate, it's your clutch.
If the engine does not rev, and you just get no power, and you just replaced parts of your ignition, then it would be wise to retrace your steps.
Are all sparkplugs connected to the proper terminals? Is your mechanical advance working properly?

I would put my money on messed up firing order.

-H

[Abadox]

Bet cha it's the catalytic converter......typical symptom!

[Cadillac Giovanni]

Well, he said the car is not shuddering, if it was a misfire, I'd imagine it would be doing a whole lot of that. If the engine is revving to a higher RPM but the car is not accelerating, then it's a tranny issue of some sort. The way i understand it, i would put my money on an exhaust blockage, most likely in the catalytic converter, but that would tend to produce some amount of shuddering as well.

[AElayyat]

I say it's the cat. You should have that check out by a muffler shop.

[chuckwagon009]

Check your fuel filter, fuel lines, and make sure 100% that your advance is working properly. If your voltage reg. went out your fuel pump could be acting stupid seeing 15-18 volts. Had this problem countless (20+) times on gmc trucks. Your dist. could bee loose and probing back/forth. Either way it seems timing/fuel, almost guarantee. After all those tests go for the exhast. Run yourself a couple bottles, directly into the carb at 1/2 throttle of SEA FOAM. Will clean your cat, out great unless the screen core cocked sideways. Test the temp b4 the cat and after if you can easily, this will tell you in a second whats goin on. Any backfiring? Does it seem like a rev limiter. (wab/wab/wab/wab)?

[Lord Cadillac]

In the event that you're exaggerating and you CAN get over 10mph... If you're just VERY SLOWING moving up in speed with no kickdown in gear, than there's a small cable that's become disconnected - Th kickdown cable..

[bishop1]

Ok here's the latest! I changed the cat converter on the old beast, it didn't help. I found a small fuel leak on the throttle body, so I replaced all gaskets and diaphram. Replaced all fuel lines, I can now get about 40mph out of the car for about 5 min. and then it goes back to the problem again I have figured out, and to those who don't know about the codes for this car. If you push the off button and the red button on your heater the codes will come up and tell you what's wrong with the car, so far I have a code 30 which is the idle speed control malf. and a 52 which is an ECM malf. I have checked everything on this car and it doesn't work, I have a new ECM coming in this weekend and I'm hoping this will solve the problem, any advice? had this problem? is my diagnosis about right? Anything at this moment would help, I have never had some much trouble with a car, but when she's healthy she's so beautiful and smooth! I guess it's worth the effort.

[The Ape Man]

Check fuel pressure under load.

[bishop1]

I changed the ecm and it didn't help, I found that there is a code for the MAP sensor, and ECM calpak, does anyone have any ideas? the car shudders now and lags when you drive. The whole time it will drive but when you put it under load the car will act up, it feels like the car goes in neutral, it is not a tranny problem, the car feels like neutral and there is no throttle response! save me please!

[DaveSmed]

Definitely needs further diagnosis. Throwing parts at it and crossing fingers gets expensive quick.

First of all, i'll recommend a fuel pressure check as mentioned before. Check it when the problem is happening by taping the gauge to the windshield.

Also, couldn't hurt to grab a vacuum gauge and check for an exhaust restriction. Hook it up and bring the engine up to a steady 1500-2500ish rpm. The vacuum reading should stablize and stay put. If it begins to drop, unhook it at the cat and take it for a quick spin. The cat is usually what gets clogged, but it could be something else too.

MAP code? got a DVOM? First make sure you have 5 volts with the key on across the outer terminals of the connector. (three wire inline) If that checks out, probe the center terminal with the connector plugged into the MAP, ground the other lead, and cross reference your voltages to a vacuum gauge using this chart: http://www.autoclassroom.com/2007/01..._a_vacuum.html