Chrysler Repair: possible fuel injection problem - hesitating, fuel injector cleaners, vacuum leaks

Question
88 Plymouth Reliant
My wife's car is hesitating when she puts her foot on the gas idling at a light. She says it is jerky when starting up when the engine has been running for about 10 minutes or so (warm). The engine also idles really high when in park. I think it could be a dirty fuel injector since we haven't run an injector cleaner through in about 5 years. Please let me know what you think ASAP as she is very worried about her "baby". Thank you in advance.
Cheers.

Answer
Hello Dayna,
I haven't ever tried fuel injector cleaners in my 2.5 throttle body injected Chrysler engine, which may be similar to yours (or you may have a 2.2 with a similar throttle body injector). The large size of the injector port and the additives in gasoline seem to make that issue fairly minimal.
On the otherhand, the high idle speed could be indicative of a faulty automatic idle speed motor or of a leak of air into the intake manifold via a cracked hose or loose fitting of a hose that is attached to the intake manifold (these are called vacuum leaks because the engine creates a vacuum in the manifold). The engine controller can automatically makeup for the leak of air by increasing the fuel input and thus balance the otherwise too lean mixture, but the result is an above specification idle speed. So the issue is do you have an idle speed motor problem or a vacuum leak?
The idle speed motor issue can be detected by the engine controller and recorded in its memory as a fault code (a two-digit number). You can read the memory yourself just by using your ignition key:
Begin a readout as follows: Take your ignition key and turn the ignition switch "on-off-on-off-on" and leave it "on". Do this switching quickly so that no more than 5 seconds elapses. Then watch the 'check engine' light to begin to flash, pause, flash, pause, etc. Count the number of flashes before each pause and make a note of them in the order that they come. The last two flash groups will be 5 in each. Repeat the readout until you have the numbers accurately (the same result, two times in a row). Then pair the numbers two at a time in the order they came, to form two-digit numbers, for example the last number will be 55 which is the code for "end of readout". Then write back and tell me the other numbers that came out and I'll see if any of them are related to your problem. The automatic idle speed motor fault is the number 25.
The presence of a vacuum leak is best determined by inspecting all the vacuum lines. The sticker on the underside of the hood is your "road map" for such an inspection. You will need to remove the air filter housing to see all these hoses. There are three plastic knobs on the top of the housing, and two hoses on the underside (one large one small) and two hoses on the front side (similarly large and small) that will need to be disconnected to remove the housing, but once it is off you can easily see all the hoses. One way to find a leak is to take a spray can of carburetor cleaner or starter fluid and put a very short (small) squirt of fluid on each hose fitting while the engine is idling and observe for an immediate change in the idle speed. But only a tiny squirt, because this stuff is flammable and can catch fire if you get it on the hot exhaust manifold below the area in question.
Those are my best suggestions on how to approach this situation. Let me know what you find from the code readout and take the effort to look over the vacuum hoses. (Let me know if you need more i.d. on those 4 hoses associatied with the air cleaner housing). I doubt that there is a chemical fix, such as injector cleaner.
Roland