Hesitant acceleration persists
JonJon68
06-19-2012, 11:52 AM
Ok folks here it goes. 1997 Pontiac Grand Prix, GT N/A 160,000....About three months ago, I started getting a misfire intermediately on my number one cylinder and started getting hesitant acceleration. Here is what I have replaced so far. New aftermarket Cat. New AC/Delco 41-401 Iridium spark plugs with AC/Delco wires. Cleaned all my sensors with the appropriate cleaner, checked my fuel pressure and was within specs. Had my coil packs tested and well within range. Cleaned my throttle body, "was clean to begin with". Unplugged my MAF and problem persists. Replaced PCV valve and air filter. I don't know where to turn next besides have my local dealership take a look at it. Yesterday I sea foamed my air intake and that seemed to straighten it out for a while but today the hesitant acceleration persists. Idle is strong and when I get to cruising speed it runs like brand new. The only thing else I can think of is maybe a stuck TCC? RPM's are where they're supposed to be with no problem with overdrive. I did take it to a local trans shop and they mentioned the TCC was sticking but according to my Tach, it has not been happening lately... Any ideas? Much appreciated!
Tech II
06-19-2012, 02:42 PM
OK, new plugs and wires.....you say coils were within range....do you mean resistance wise? You should do a coil output test with a spark test.....
If ok, then have you checked compression? Does this happpen at idle or when under a load?
If at Idle, I would check valve springs, for a broken spring.....
If ok, could be an injector problem.....
Assume 3.8.....losing coolant?
If ok, then have you checked compression? Does this happpen at idle or when under a load?
If at Idle, I would check valve springs, for a broken spring.....
If ok, could be an injector problem.....
Assume 3.8.....losing coolant?
JonJon68
06-19-2012, 02:44 PM
Not losing coolant. I replaced both upper and lower intake gaskets a few years ago. I just now got a code PO121 so I'm going to clean my TPS with throttle body cleaner? In any event I have a new one on it's way from Rock Auto
JonJon68
06-26-2012, 06:38 AM
Ordered a new OEM TPS and problem seems to be corrected.
Automotive Network, Inc., Copyright ©2025