Can someone tell Sal Collaziano I need his help. I have a hesitation problem on my 89 Sedan Deville with a 4.5! The throttle body is spotless. Engine has only 74,000 miles on it! When I am driving down the road I keep getting a bucking like the car is running out of gas or breath. Is this an EGR problem and I have searched the forum for how to clean it but I can't find anything. I am not too computer savy. Help

You mean Bb0b right.....I don't know if he's posting anymore.

As for what may be causing you problems, its hard to guess.
Is there a way to pull DTC codes off the dash to see if its triggered anything?
It could many things, everything from clogged injectors/filter/ignition related (wires/coils).....but I am just throwing possibilities out there.....need more info

You might want to check error codes. It sounds like fuel starvation. The trick is to connect a pressure gage to your fuel line with a long enough rubber hose so that you can tape the gage to your windshield and read it while driving. That will give you an accurate reading under load. If it is weak you probably need to replace your fuel pump.

You might have more luck with this over in the 4.5 section.

If it was an EGR problem, it would more likely give you idle problems. My first gander would be at the plugs. Are they misfiring? How does the car idle?

The gas filter and air filters were changed recently. The ideal is still good. Went through OBD and no codes. Any suggestions based on this information? How do I post this over on the 4.5 board? Sorry computer skills are limited!

Have you checked for spark yet? It is possible to not get clean spark and still not show codes. The OBD 1 north*s don't show a code for failing coil packs. They will show a code for a bad misfire however. Something similar is probably true with your 4.5. I don't believe you are getting a bad misfire. But you aren't getting clean steady spark either.

I would suggest checking the fuel injectors because it is such an EASY check to make. With a mechanics stethoscope listen to each injector. They should click very distinctly during idle. After listening to each injector, meter the coil of each injector. They should read between 12 and 16 ohms. As fuel injectors deteriorate the resistance of their coils becomes less and less. Anything less than 12 ohms should be considered suspect. With a flashlight LOOK very closely at the base and fuel rail ends of the injectors for any signs of leakage.

Doesn't that engine have throttle body injection?


Check the fuel pressure. It should be constant 10 PSI. There is a schraeder valve fitting at the throttle body on the fuel inlet line to make checking the pressure easy.