1991 P30 454 intermittent surging, power loss
Hi everyone, I just bought this 91 Damon Challenger P30 454 TBI and it has this intermittent issue at slower speeds. It doesn't do it all the time. It idles fine, has trouble accelerating, power l...
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**New update**
I rebuilt the TBI throttle body. I really did not find anything wrong with it, but it's done.
Bought a new A1 Cardone distributor. It has the same reluctor design as the original GM. It also has two holes with screens on the base plate, presumably to address the moisture issue inside the distributor. I like this updated design. The new distributor was easy to install with no problem.
Spark plugs were Autolites, I replaced them with AC/Delco.
Spark plug wires were the original AC/Delco. One of them had a large split in it, near cylinder #1. I installed a new set of AC/Delco wires.
**Test drove, no change. Problem is still present.** It bogs down when accelerating at low speeds.**
I tried disconnecting the MAP sensor and guess what, It runs much better!!
Ordered a new AC/Delco MAP sensor, installed it and test drove. Ran good, but only for 15 minutes and the problem is right back.
Disconnected the new MAP sensor, and it runs much better! The hesitation is still there a little bit, but it runs significantly better with the MAP disconnected.
Every time I disconnect the MAP, I plug the vacuum port. FYI
I still haven't looked in to pulling codes on this, but the CEL (Service Engine Soon) light comes on immediatley when the MAP is disconnected and turns off when it is reconnected.
I am starting to wonder if the PCM is bad.
I should have bought a FORD! This thing is very frustrating.
I rebuilt the TBI throttle body. I really did not find anything wrong with it, but it's done.
Bought a new A1 Cardone distributor. It has the same reluctor design as the original GM. It also has two holes with screens on the base plate, presumably to address the moisture issue inside the distributor. I like this updated design. The new distributor was easy to install with no problem.
Spark plugs were Autolites, I replaced them with AC/Delco.
Spark plug wires were the original AC/Delco. One of them had a large split in it, near cylinder #1. I installed a new set of AC/Delco wires.
**Test drove, no change. Problem is still present.** It bogs down when accelerating at low speeds.**
I tried disconnecting the MAP sensor and guess what, It runs much better!!
Ordered a new AC/Delco MAP sensor, installed it and test drove. Ran good, but only for 15 minutes and the problem is right back.
Disconnected the new MAP sensor, and it runs much better! The hesitation is still there a little bit, but it runs significantly better with the MAP disconnected.
Every time I disconnect the MAP, I plug the vacuum port. FYI
I still haven't looked in to pulling codes on this, but the CEL (Service Engine Soon) light comes on immediatley when the MAP is disconnected and turns off when it is reconnected.
I am starting to wonder if the PCM is bad.
I should have bought a FORD! This thing is very frustrating.
