I installed a 97 5.2 out of a wrecked van in the 52 Dodge pickup I'm building. I left the EFI on it, so the engine is completely stock except for modifying the harness. It starts an runs great under lite throttle. It will run down the highway at 55 mph all day. The problem is when I start to roll in to the throttle it acts like its starving for fuel. It bogs down and has a slight back fire. As soon as I roll out of the throttle it smooths out and runs fine. The history on this engine is it sat idle in the van for 15 years. Milage is around 60,000 miles. I pulled the intake and pan, every thing in side looks fine. It has good oil pressure. The only code it is throwing is high voltage on the battery temp sensor. I'm thinking dirty clogged injectors may be causing the problem. I'm going to try adding a bottle of injector cleaner to the fuel and see what happens. It also has a new crank sensor, cam sensor, distributor cap, rotor, fuel pump and regulator on it. I checked for distributor shaft side play and it is good. Any other suggestions beside what I have already done and adding injection cleaner?

does it only do that under load, or can you replicate it when bliping the throttle?

2nd gear at the same speed?

if you can hold speed at higher rpm then it probably isn't injectors.

I lean towards checking the tps but no real evedence yet and I wouldn't just throw parts till you check a few other things.

How's the fuel pressure?

It does it under load and when I blew the throttle. I have another throttle body I'm going to try if the injector cleaner doesn't fix it. I had a similar problem on a Ford 5.0. Replacing the tps fixed it.

Haven't checked the fuel pressure yet.

Bet its a MAP sensor, I had a 97 1500 5.2 4x4 in the shop yesterday did exactly like you describe, engine vacuume and atmosphere were reading the same, threw one on out of my parts pile and it ran like new. I think that was the first time I seen a bad MAP on a magnum engine.

Thanks, I have a low milage 5.9 setting in the shop. When I get back home next week I'll swap the MAP out of the 5.9 and see what happens.

What codes are being thrown?

Doesn't make any sense to throw parts at it without looking at what the computer is telling you.

The only code its throwing is battery temp sensor voltage to high. That can be fixed by changing the diode, which we will do to turn off the check engine light. Parts aren't a problem. I have another engine in the shop I can get parts off of, plus a buddy that works in a salvage yard that can get me no cost parts to troubleshoot with.

Make sure the dist is indexed right. Of course the dist does not set timing as its basically a cam sensor on that eng but it has to be indexed to the crank sensor as I had some that would run bad above about 2 to 3000 rpm when the dist was out of index a bit. You can check it either with a digital voltmeter or a scan tool if your scan tool has that function. Good luck with it.
I am guessing its still charging ok as the PCM should use a limp figure for battery temp with that code set as normally the higher the temp the PCM see's from the battery temp sensor the lower the target charging volts ? Ron

Ron, thanks I think you may have hit on the problem. Never having worked with these engines I'm learning as I go here. I just finished researching dist sync and it sounds like the problem my engine is exhibiting. I'll check the sync before I do anything else.

Problem fixed. The injectors were dirty. Three bottles of injector cleaner and two tanks of gas and the initial problem is gone. Then another problem popped up the engine goes into shut down mode at full throttle. After checking every thing over for the tenth time I checked the throttle body butter fly against the peddle position. The throttle body was going over center with the peddle all the way down, throwing the TPS signal out of whack. So I installed an adjustable stop under the peddle and adjusted it so the TPS signal is correct at full throttle. FIXED! My head hurts after trouble shooting this one.